Gigantamax raid catch rate bug (maybe?)

So I was under the impression that Dynamax and Gigantamax raids had a 100% catch rate if you are playing offline or hosting an online raid.

This is backed up by a few of the reliable pokemon websites (Serebii, bulpedia, etc) however I have now had the pokemon escape on 3 separate occasions.

First was a 4 star hatrene and the latest was a 3 star corviknight. I don't remember the second one specifically but I can say with certainty they were all offline.

Has this happened to anyone else or am I crazy?