
Hmmm ... That is maybe a problem with your actor's sprites in your
data file. Try to delete the "bugged" animation sprites from your data file and in GE, reload them to your actor using the source sprites. Save, close and reopen GE.
What happen ?
Also, verify both actors' sprites name in your Data file. Ex, if first and second Actors' sprites are both called "Robert#n" and that they are stocked in your data file, reopening GE will cause the problem you are having.