Technician came and updated the MP40 to 4.98 and LP in Cab2 to 4.33 on 2017-12-22. Had to restore all settings from the backup we did as it did a clean install / wiped all settings.
Still had trouble with lights.
Did another hard power-off restart and things worked fine until Tuesday, 2017-12-26.
During the update, didn't realize until Tuesday, 2017-12-26 that on the SVMi-20E mailboxes 201-220 were all wiped out along with any saved (orphaned) messages. Had to re-create them all.
This morning, 2017-12-28, Cab2, Slot3, Chan6 quit working. No lights at all on the phone. Had been working earlier this week. Moved from Cab2, Slot3, Chan6 to Cab2, Slot3, Chan1 and it started working again.
I've contacted the tech and asked them to contact Samsung regarding this issue. I'm not sure what else I can do.