I was offline yesterday, and actually happens twice. I got a screenshot of it once. I'll check and see if any of the saves were prior to the event, but I will check later.
After you finish one engagement, the game will CTD.
The first time it happened, one of the two let me choose to engage, without having an engagement already, and then went into double mode. The second time, they were both automatic engagements. Therefore, I think you are correct in assuming that it's a timing issue.