Can't say I've noticed that one, though it occasionally loses panels that I have docked. Mind you, I think it's done that since it was PageMaker (I found a training guide for PageMaker that I wrote a bazillion years ago, it's not changed much, though I suppose if it ain't broke).
The only other problem I've noticed is, for some reason, Affinity Designer won't import text styles, which seems a bit bizarre, but it works fine on my un-updated Macbook yet not my updated iMac. A minor issue as I mostly start from templates that have the styles but a bit strange.