Every firefox window defaults to 'show on all desktops' with windows 10 after trying the 'show this window on all desktops' feature once

I tried Windows 10 ‘show this window on all desktops’ once with Firefox — now all new Firefox windows are pinned to all my desktops.

Cannot find anything on google due to the words ‘pinning’ and ‘desktops’ mostly bringing up results related to the sidebar and not to the multiple-desktops feature.

Here’s a screen recording of it happening: https://streamable.com/mb114g