Not that this is an issue itself, naturally the polling will fault but the report probably could be suppressed if the reason is that the modem is in a disconnected state because it was invoked by the user.
I'm not being picky, I just noticed that this was showing up in the log and may cause confusion for some.
In the following log I started VarAC, Clicked the button and disconnected the modem, and then clicked and reconnected the modem.
23/12/2022 19:36:26 - Connected to VARA modem
23/12/2022 19:36:26 - Setting Bandwith to 500Hz
23/12/2022 19:36:26 - Change frequency: to last frequency used before shutdown.