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.
How to make the perfect "Half-Hitch" knot or any other boyscout knot in 3 easy steps...
1. Remove your meter leads from the meter and very carefully return them to their storage case or bag.
2. Wait 2 seconds
3. Very carefully remove your meter leads from their storage place and enjoy your new knot!