Over the weekend, I looked at my list of prioritized resources in my library and noticed that there was a lot of duplication and that it wasn't listing the collections any more but individual tities repeated multiple times. I'm using 4.3 beta 2 (4.30.0.0208).
I took the time to delete them, but couldn't find a way of deleting more than one at a time. Initially, with a long list, it takes a long time to delete each one, but as the list shortens, the task gets easier. Incidentally, it would have been nice to be able to click-shift-click to select a range and delete them all at once.
Once I re-added the resources, the prioritized list seems to be fine again.