does cycling power make the problem go away?
there was a service bulletin for a similar situation..but it was supposed to be fixed on units by serial numbers beginning with 827. perhaps yours slipped through or the problem is bigger than they originally thought or you got a replacement board before the fix from a parts distributor.
call the local Trane office and ask for: RT-SVB35A-EN
the service bulletin describes a field modification for the existing board.
as always, make sure that the RTRM board is the latest version...i think it is up to version 8.'something' now...it may be higher. the RTRM board is the almighty board, and yes, it can affect the ignition board.
"Pimp My Service Truck"...that's a show I would watch!
Get me some rims and spinners, purple LED lights underneath, a disco ball and lasers....yeah!!! And make it a low rider!