using version 4.11.4 in Debian wheezy (or the newest version from Kubuntu), the rule strings for camera:/ and mtp:/ are the same: "Open with File Manager".
When plugging in an android phone, in this case my Galaxy S2 (i9100) in MTP mode, KDE detects it with both rules and displays two identical possibilities how to open it. 

Reproducible: Always

Steps to Reproduce:
1. Plug in an android device which is switched to MTP mode
2. watch the "devices" plasmoid open

Actual Results:  
There are 3 actions, two of them identical: "Open with File Manager".

Expected Results:  
Distinguishable actions for the "two different devices".

Go to systemsettings > "Device Actions"  and watch out for "Open with File Manager", being there 4 times, for different device types. They all are named the same, so the user can not distinguish what these mean if more than one of them are shown in a device plasmoid. Worse, the German translation of these identical strings are different, so in German you have "Mit Dateimanger öffnen" and "Mit Dateiverwaltung öffnen" which causes even more confusion.
The camera:/ rule even does NOT call dolphin, but "kioclient exec camera:/" - whatever is associated with the kio-slave "camera:" will open it. It is not guarantied that this will be dolphin, right?

There are some solutions to this IMHO, all done with few effort. I would simply rename the camera rule to "Open as camera", done.
The other one would sound better: "Open as media device", or at least "Open with File manager as media device" - but this seems a bit long to me.

This is not related to bug #336523.