We noticed this issue when implementing horizontal rule for our rich text editor, and I noticed that it’s also an issue in the central example on prosemirror.net. I tested in Chrome, Edge, and Firefox, and found that it didn’t affect the latter.
To reproduce: Insert a horizontal rule at the end of the document. Arrow down until you’ve passed it, then arrow down once more. The page scrolls down, nearly to the bottom of the page.
If anyone else has noticed this and knows of a workaround, please share 