I get that error all the time on iPadOS when I browse the Reddit front page, paginated-style, viewing videos by clicking the thumbnails to expand the video on-page.

I believe it’s simply a memory leak. I fix it by copying the URL, closing all tabs, and “hard” terminating Safari (flick up to display all recent apps, flick up to remove Safari from the list). Then I reopen Safari, paste back the URL, and continue on.

On occasion I have had to do a full shutdown and restart. Have you tried that?