Comment 10 for bug 1852183

It's useful to know that a recent update to mutter is at least partly to blame for this, as I cannot reproduce the issue on versions older than 3.34.

Mutter 3.34 introduced a new clipboard manager: https://www.phoronix.com/scan.php?page=news_item&px=GNOME-3.34-Clipboard-Manager

However, LibreOffice does seem to be doing something strange in its type requests from the clipboard (stand by for a comment from a colleague with more mutter knowledge), so I suspect there may be fault on both ends here.