i have seen this happen a few times (not always and i am not sure the scenario that causes it). it has not happened when i restart scheduler and ACP during the day. it does happen "sometimes" when i just leave everything running from one night to the next. here is an example from two nights ago.
the observatory starts up and looks like everything is connected fine but when it comes time to run the auto flat script (a few minutes later) the telescope has disconnected and the flat run fails. if i stop the dispatcher and restart it, everything runs fine; startup runs again and auto flats run and the night session runs without incident.
attached is the scheduler log and the two startup scripts that were run.
startupobs@193238 shows the telescope connected but a few moments later when the auto flat script ran it failed because the scope was not connected. i restarted the dispatcher and startupobs@195630 ran — reconnected the scope and every was fine after that.
scripts and my startupobs script are attached. the only changes i made to startup obs script were to the program startup section (and that works fine)