investigating SA format EXP not sticking when commanded by RECEE even mark switch

[Hulkbust44]

When the RECEE event mark switch is pressed with the TDC cursor over an air-to-air MSI track on the SA format, the SA EXPand function does not stay. The displays flashes to the EXPand but then back to the standard view. This happens seemingly at random. Track below.

EXP_BUG.trk