libnm-qt-0.5.0git.1342705341 is not the libnm-qt version we maintain. If OpenSuse is patching the libnm-qt we implement then I cannot help here. Keep in mind that libnm-qt does not maintain binary compatibility, so everytime we upgrade libnm-qt you have to recompile Plasma NM.

It's just the naming, and not official package, i have a project on OBS for master git. You can see when the last pull was here:
https://build.opensuse.org/package/files?package=libQtNetworkManager&project=home%3Asumski%3AKDE%3AUnstable%3ASC
(Which pulls from git://anongit1.kde.org/libnm-qt.git)
https://build.opensuse.org/package/files?package=NetworkManager-kde4&project=home%3Asumski%3AKDE%3AUnstable%3ASC
(which pulls from git://anongit.kde.org/networkmanagement)

Why are you using 0.5.0 as the version? The current version is 0.9.0. I also cannot reproduce this problem here and I use master version most of the time. Again: you have to recompile Plasma NM when libnm-qt is upgraded (like two weeks ago), have you done that?

OBS functions exactly in this way - if package A is changed, and package B depends on it, it also gets recompiled. So Plasma NM is surely rebuild against libnm-qt.
Tommorow i'll post diff of both Plasma-NM and libnm-qt between latest pull, and latest master.
As per versioning - i'll change that :)

Created attachment 76618 [details]
New crash information added by DrKonqi

plasma-desktop (0.4) on KDE Platform 4.9.98 using Qt 4.8.4

- What I was doing when the application crashed:
Turned off WiFI and turned it on again. Crashes *always*. No matter if using rfkill, or NM applet. Plasma just goes down. (This was the first time where I got a DrKonqui to provide a backtrace, in the other cases Plasma crashed and restarted without a message)

-- Backtrace (Reduced):
#6  InterfaceDetailsWidget::handleConnectionStateChange (this=0x2730bf0, new_state=NetworkManager::Device::Disconnected, old_state=<optimized out>, reason=<optimized out>) at /home/kaiuwe/Projekte/networkmanagement/applet/interfacedetailswidget.cpp:589
[...]
#8  0x00007f8ad132f2e0 in NetworkManager::Device::stateChanged (this=0x3ce92e0, _t1=NetworkManager::Device::Disconnected, _t2=NetworkManager::Device::Unavailable, _t3=NetworkManager::Device::SupplicantAvailableReason) at /home/kaiuwe/Projekte/libnm-qt/build/device.moc:223
#9  0x00007f8ad132eabb in NetworkManager::Device::deviceStateChanged (this=0x3ce92e0, new_state=30, old_state=20, reason=42) at /home/kaiuwe/Projekte/libnm-qt/device.cpp:448
#10 0x00007f8ad132ebbb in NetworkManager::Device::qt_static_metacall (_o=0x3ce92e0, _c=QMetaObject::InvokeMetaMethod, _id=2, _a=0x7fff01f9ea60) at /home/kaiuwe/Projekte/libnm-qt/build/device.moc:124
[...]
#12 0x00007f8ad134b7d2 in OrgFreedesktopNetworkManagerDeviceInterface::StateChanged (this=0x34e13c8, _t1=30, _t2=20, _t3=42) at /home/kaiuwe/Projekte/libnm-qt/build/nm-deviceinterface.moc:183

Please, always send the version string of Plasma NM you are using.

Version 0.9.1.70 (master 20130115)

I think the problem is reason == NetworkManager::Device::Unavailable, that means the wifi card is not available anymore and then m_iface object is invalid when Plasma NM tries to detect the interface type. I am working on a patch to use QPointer to track NetworkManager::Device objects and then fix that kind of problem once and for all. Unfortunately I have not had much free time so the patch is at early stage now. This is the same kind of problem of that causes the bugs below:

https://bugs.kde.org/show_bug.cgi?id=312635
https://bugs.kde.org/show_bug.cgi?id=312638
https://bugs.kde.org/show_bug.cgi?id=313164
https://bugs.kde.org/show_bug.cgi?id=313297

All bugs above could be marked as duplicate of this one since the source of the problem is the same although the steps to reproduce differ a lot. Anyway, I can add a workaround to do try to use the m_iface when reason == NetworkManager::Device::Unavailable. That should prevent this crash until my QPointer patch is ready.

Git commit 3bcb9c6d3769ba795a453b4d6d88217061ea63f6 by Lamarque V. Souza.
Committed on 22/01/2013 at 02:33.
Pushed by lvsouza into branch 'master'.

Add workaround to prevent crash.

M  +1    -1    applet/interfacedetailswidget.cpp
M  +1    -1    plasma_nm_version.h

http://commits.kde.org/networkmanagement/3bcb9c6d3769ba795a453b4d6d88217061ea63f6

Git commit f57fb13279d491391e61663e200cf667f4152a23 by Lamarque V. Souza.
Committed on 22/01/2013 at 02:33.
Pushed by lvsouza into branch 'nm09'.

Add workaround to prevent crash.

M  +1    -1    applet/interfacedetailswidget.cpp
M  +1    -1    plasma_nm_version.h

http://commits.kde.org/networkmanagement/f57fb13279d491391e61663e200cf667f4152a23

Created attachment 77918 [details]
New crash information added by DrKonqi

plasma-desktop (0.4) on KDE Platform 4.10.1 using Qt 4.8.4

- What I was doing when the application crashed:
Disabled WiFi, re-enabled Wifi, the list of found WiFi networks appeared, and then Plasma crashed. On currentmost master branch with QML interface.

-- Backtrace (Reduced):
#5  0x00007f82aa95c994 in InterfaceDetailsWidget::handleConnectionStateChange (this=0x2ef8e10, new_state=NetworkManager::Device::Disconnected, old_state=<optimized out>, reason=<optimized out>) at /home/kaiuwe/Projekte/networkmanagement/applet/interfacedetailswidget.cpp:589
[...]
#7  0x00007f82aa01a2e0 in NetworkManager::Device::stateChanged (this=<error reading variable: Could not find the frame base for "NetworkManager::Device::stateChanged(NetworkManager::Device::State, NetworkManager::Device::State, NetworkManager::Device::StateChangeReason)".>, _t1=<error reading variable: Could not find the frame base for "NetworkManager::Device::stateChanged(NetworkManager::Device::State, NetworkManager::Device::State, NetworkManager::Device::StateChangeReason)".>, _t2=<error reading variable: Could not find the frame base for "NetworkManager::Device::stateChanged(NetworkManager::Device::State, NetworkManager::Device::State, NetworkManager::Device::StateChangeReason)".>, _t3=<error reading variable: Could not find the frame base for "NetworkManager::Device::stateChanged(NetworkManager::Device::State, NetworkManager::Device::State, NetworkManager::Device::StateChangeReason)".>) at /home/kaiuwe/Projekte/libnm-qt/build/device.moc:223
#8  0x00007f82aa019abb in NetworkManager::Device::deviceStateChanged (this=<error reading variable: Could not find the frame base for "NetworkManager::Device::deviceStateChanged(unsigned int, unsigned int, unsigned int)".>, new_state=<error reading variable: Could not find the frame base for "NetworkManager::Device::deviceStateChanged(unsigned int, unsigned int, unsigned int)".>, old_state=<error reading variable: Could not find the frame base for "NetworkManager::Device::deviceStateChanged(unsigned int, unsigned int, unsigned int)".>, reason=<error reading variable: Could not find the frame base for "NetworkManager::Device::deviceStateChanged(unsigned int, unsigned int, unsigned int)".>) at /home/kaiuwe/Projekte/libnm-qt/device.cpp:448
#9  0x00007f82aa019bbb in NetworkManager::Device::qt_static_metacall (_o=<error reading variable: Could not find the frame base for "NetworkManager::Device::qt_static_metacall(QObject*, QMetaObject::Call, int, void**)".>, _c=<error reading variable: Could not find the frame base for "NetworkManager::Device::qt_static_metacall(QObject*, QMetaObject::Call, int, void**)".>, _id=<error reading variable: Could not find the frame base for "NetworkManager::Device::qt_static_metacall(QObject*, QMetaObject::Call, int, void**)".>, _a=<error reading variable: Could not find the frame base for "NetworkManager::Device::qt_static_metacall(QObject*, QMetaObject::Call, int, void**)".>) at /home/kaiuwe/Projekte/libnm-qt/build/device.moc:124
[...]
#11 0x00007f82aa0368da in OrgFreedesktopNetworkManagerDeviceInterface::StateChanged (this=<error reading variable: Could not find the frame base for "OrgFreedesktopNetworkManagerDeviceInterface::StateChanged(unsigned int, unsigned int, unsigned int)".>, _t1=<error reading variable: Could not find the frame base for "OrgFreedesktopNetworkManagerDeviceInterface::StateChanged(unsigned int, unsigned int, unsigned int)".>, _t2=<error reading variable: Could not find the frame base for "OrgFreedesktopNetworkManagerDeviceInterface::StateChanged(unsigned int, unsigned int, unsigned int)".>, _t3=<error reading variable: Could not find the frame base for "OrgFreedesktopNetworkManagerDeviceInterface::StateChanged(unsigned int, unsigned int, unsigned int)".>) at /home/kaiuwe/Projekte/libnm-qt/build/nm-deviceinterface.moc:183

I just got this crash, but when I tried to update my libnm-qt checkout, I get an error because it requires NetworkManager 0.9.8.0 and OpenSUSE-12.3 has 0.9.6.4. How can I solve this?
I didn't find a branch for 0.9.6.

There is no branch for 0.9.6 and other libnm-qt developers pushed some changes that require NetworkManager 0.9.8 (the current stable NetworkManager version for more than three months now). You will have to upgrade NM or stick with the older version, sorry.

*** Bug 320942 has been marked as a duplicate of this bug. ***

Created attachment 81577 [details]
New crash information added by DrKonqi

plasma-desktop (4.10.5) on KDE Platform 4.10.5 using Qt 4.8.4

- Unusual behavior I noticed: 
Solo pasa cuando desconecto Modem de Internet Usb marca huawei E353 4G

-- Backtrace (Reduced):
#6  0x00007f901254814e in InterfaceDetailsWidget::handleConnectionStateChange(int, int, int) () from /usr/lib/kde4/plasma_applet_networkmanagement.so
#7  0x00007f901252b44f in InterfaceDetailsWidget::qt_static_metacall(QObject*, QMetaObject::Call, int, void**) () from /usr/lib/kde4/plasma_applet_networkmanagement.so
[...]
#9  0x00007f9011a026ea in Solid::Control::NetworkInterfaceNm09::connectionStateChanged(int, int, int) () from /usr/lib/libsolidcontrolnm09.so.4
#10 0x00007f9011a024c3 in Solid::Control::NetworkInterfaceNm09::qt_static_metacall(QObject*, QMetaObject::Call, int, void**) () from /usr/lib/libsolidcontrolnm09.so.4
[...]
#12 0x00007f90110993ce in NMNetworkInterface::connectionStateChanged(int, int, int) () from /usr/lib/kde4/solid_networkmanager09.so