Well, problem solved!
What was going wrong was that I had one action (show correct img if question is correct else show incorrect img). That else needed another if, (question is not empty). So I created a separate action for the incorrect image with multiple conditions (question not correct AND not empty) and it worked just fine.
I also got rid of the OnTimer RunActionGroups actions because that wasn't the case.
Thanks to Randy from Lectora helpdesk and everyone else who took the time wondering about my problem!
