@Holly130 Yes, this happened to me multiple times - Very disconcerting. Initially I traced it back to when I changed my price for a period of time and put in the 'from' 'to' dates. All the dates blocked by me suddenly opened up when the price changedx. I didn't notice this for some time, however - Only when it happened a few more times. Mercifully, nobody booked the dates that I am not available to host.
So I thought I would just not ever make that mistake again. Yet, mysteriously, for no apparent reason, my dates opened up again. I now have taken screen shots of every single month showing my blocked dates in case it happens again and I get a booking that will need cancelling. Proof that the issue was not on my end.
It would be wonderful if this oft-reported bug would get fixed some day by ABB. We are always reminded how bad it is to cancel; the cancellations that come about from buggy software are just as egregious, if you ask me. Same result: Guest is cancelled.