Some people have reported that their DM02 or DP03 button pressed causes the system to lose communications and hang.
It appears that they have used the Action "Activate Doorphone" in the Misc Events > Doorbell Response
Now the purpose of the Activate Doorbell Response is to activate the doorphone when assigned to a zone input, so that it can have the function of a doorbell. It was actually a leftover from Comfort I pre-doorphone days
The modern door stations DP03 or DM02 do not need this action to work as a doorphone as it is already built into its functionality
Using activate doorphone on the doorbell Response actually calls the Doorbell Response again so it results in an endless loop which causes the system to reset
Future Comfort firmware will prevent this action from takng effect even when assigned to the Doorbell Response in order to try to make everytning as idot-proof as possible