Just wanted to say for people reading that, generally, playing with faster speed should not be a problem. Changing the speed back and forth, now that could cause bugs if you're unlucky.
The bug in question (probably) only happens with certain, relatively rare events that you must play more than once. So if someone plays such an event the first time, and then change the speed to faster before playing the event again to complete it, it may bug a flag for that event.
I think this is when the bug happens, I just found it hard to fix because the code handling all that is quite complex. I did try to fix it in v0.12, doing a "I hope this works" fix, but obviously it wasn't good enough since you had a similar bug again. The bug is rare because there are not many of these events, and it's only in that window until you complete it that the bug can happen if you raise the speed.