As per the image, Safari has been showing the roll-over popups all the time on all Stack Exchange sites. I've tried disabling all ad blockers but to no avail. I'm on MacOS 11.2.3, using Safari 14.0.3.
Edit: A stopgap solution was to add
.s-popover.s-popover__tooltip to the CSS Hide Elements list in 1Blocker.
The downside is that this completely removes the tooltips so that they can't be seen even when hovering over the buttons.