Funny behavior of starred favorites does seem to be an issue right now. But, this only appears to be an issue visually on the map. The content of your starred favorites is still there. From the Maps app's main screen, click the "person" icon in the top right. Under "Saved Places" click on "View All" and you should see all of them, irrespective of whether they are rendering properly on the map.
Originally Posted by
VT_hawkeye
The biggest problem for me is that new Google Maps quits displaying stars for starred items/"My Places" for no apparent reason, and I have to kill the app completely in order to make it reload and display stars again. It's incredibly annoying since my usual trip habit is to star everything in advance, then identify geographic clusters and operate on the fly within the clusters -- it makes picking my next stop a five-step process rather than one.