Sometimes when I boot-up my Kubuntu the network icon goes RED and wont show any wireless Networks, So I reboot my PC and then I can regain my wireless connection. I am using the latest version of Kubuntu, Kubutu 16.10, KDE Plasma Version 5.7.5, KDE Frameworks 5.26.0, QT 5.6.1 and kernel 4.8.0-28-generic Os type 64 bit
Check if output from "nmcli device wifi list" is empty when you don't see any wireless network. If so, then the bug is in NetworkManager or somewhere else, but I would start with report in NM bugzilla.
Closing. Didn't get any response from the reporter and also this problem doesn't seem to be in plasma-nm.