Mike this folder had multiple day visit in the zoo in it so might get slit into multimple events?
This will definitely be split to separate events, as date is the main factor here. This is why I asked you to scroll and use time line to try to locate those missing files in separate events.
So, as I just said, there is definetly more to that, then just add to album and here you go. At least date seems to be at play. However, in my tests I was using files with different dates too, but it still worked fine. So if there is any other pattern that you can identify - that would help a lot. I hope you understand that it is close to impossible to fix a bug that you cannot reproduce.