(me: 3 days ago) To the best of my knowledge, the issues in map view have been resolved in the current backstage build; they were, as far as we know, experienced only by a handful of people and chiefly involve older computers.
Thanks for the additional report. Pier Rubesa is the second user with the problem who is not using an older iMac with rotating media; that’s helpful. The pattern is consistent with interference from some system utility or peripheral, but again no consistent culprit has been seen.
Unfortunately, none of our machines is afflicted, and no one in the backstage program experiences the problem, either; debugging this is, in part, flying blind.