On a Product page with just a few "cards", such as the Core tab, if I move the mouse back and forth between two cards, more empty cards get added to the display. This is in Firefox v 89.0. I don't see this in Chrome on the same page.
Thanks for the detail on this and the video. I was able to replicate and note that it happens on both the Core and Capabilities tabs so we'll raise an issue for that with our support team and I'll add to our Known Issues.