FYI.
Original comment that turned out to be wrong. See post below instead …
Moved my WiFi 2.4GHz to channel 10 here the other day, and that totally jammed my Zigbee network on channel 25. Worth checking if things doesn’t work as expected.
1 Like
Yes. Turned out it was not the problem I experienced at all.
What fooled me was that the last thing I did before having trouble adding a switch was changing the WiFi channel. Had dropouts playing my Squeezeboxes and WiFi analyzer showed we were 6 neighbors on the same channel. Helped to move to a quieter one.
That was a week ago.
Just now I had the same problem, a new switch adds fine, but drops out of the network after 10-15s.
After numerous attempts I tried pulling my Conbee I and reinserted it, and then the switch stays connected. Must have done the same last week without thinking about it.
Will edit the title of this thread, because the statement is wrong. 
Experienced the same with a HUE SML003 today.
Joined fine, but dropped out of network.
Had to re-plug the Conbee I to make it stay …
thanks for the heads up, helped me with a non-responsive SML003 today (did not replug raspbee ii, but reboot right after pairing).
Amounts to the same I guess.
Something is going stale after a certain uptime.
Didn’t have the time to collect before /after logs.