If pawns chose to use meditation for joy, they will continue to meditate even when their recreation bar is filled. This happens to pawns without a psy bar, but I suspect this is linked to the changes for meditation + psy, since it has been added to the game about the when Royalty got released.
https://steamuserimages-a.akamaihd.net/ugc/1841409612959002311/0775D670895479AC40EA71268F51B5D9A073C65A/
Thanks for the bug report. I could have sworn I reported this bug internally back during Royalty testing (I've been doing this too long). I can't find it in our bug tracker though, so I'll post it again.