The fact that the T relay stays energized it the key here.
Per your schematic, this game has 3 NO tilt switches and 1 make/break switch on the R relay that could cause this. Locate and verify all 4 switches are open. My bet is on the R relay-either the MB switch is not opening, or the relay itself is not pulling in. That coil may be fried, as I think it is on all the time. Also (more likely), there might be an issue with the SB2 switch stack causing the R not to pull in.
Good luck!