Under certain circumstances, extra PLAYER MOVEMENT, PUT OBJECTS ON OTHERS and WEAR OBJECT general tasks are being added to a game file every time it is opened. If they are not deleted before a blorb or an executable of the game is saved, these extra tasks can make the game unplayable.
Update: My laptop at work, on which this bug was happening as well as at home, has been replaced with a new one. I don't know what is different about this new laptop but the bug has stopped occuring. It still occurs on my laptop at home though.
CORRECTION!!! It is still happening on my work laptop. Opening and closing game files shows different combinations of extra PLAYER MOVEMENT, PUT OBJECTS ON OTHERS and WEAR OBJECTS general tasks. However, two game files are not affected at all (which is why I thought it had stopped happening).