Yes, with CAN-bus you better have a battery that is fresh & fruity, otherwise you will indeed run into a heap of problems, left, right and center.
I strongly recommend a good battery-charger (e.g CTek) with sufficient charging-current (2 amps and up) to keep your battery topped-up.
Or have good long ride (minimal an hour) every 2 weeks, that will charge the battery too.
When the voltage drops too much due to a flaky battery, CAN-bus will start to shut-down non-essential electronics.
Most notably, the radio and accessoires-connectors, first.
But if that fails to raise the voltage, other things may start to fail too.
Correct, the GS911 at this moment can identify the presence of the radio and read fault-codes about it supposedly.
(I never have seen fault-codes for the radio though)
Glad it was such "minor" issue and got resolved.