I just reviewed the code to see what I could find here. I've only seen a handful of reports about this, while it seems to be working for most users. My immediate thought was the usual hardware bindings. After my code review, I'm sill inclined to believe that is where the issue lies.
The light will illuminate only when...
The standby alternator bus is connected to the main bus (will happen when the switch is thrown)
The main bus is at at least 16V (should always be the case during normal operation)
When the alternator is energized.
This last point is likely where the issue is. This can happen in two ways...
When hardware/software is sending the associated alternator event to activate the alternator.
When correctly set by the code in the aircraft, when...
a. The main generator is off.
b. The main generator is on, but the battery is discharging at more than 5A.
If you cannot find any type of hardware or software input that might be affecting any of the conditions listed above, then the best thing to do would be to sent me screenshots of everything you can think of. This would include the tablet's live schematic, the multi-meter, the whole panel with all the annunciators and engine instruments, and if anyone is ambitious, perhaps some of the underlying variables discussed above, if you're familiar with reading them in 3rd party applications. Thanks for any help!