I also noticed this recently.
"Close Tabs & Clear Data" (via the three-dot menu) should delete recently closed tabs – as should clearing the history via settings.
fish Safari doesn't seem to be able to clear this list either
Safari clears recently closed tabs when history is cleared (on desktop at least)
Vlad Is there a browser that has this option?
Firefox and Chrome also have this feature and they both clear recently closed tabs when history is cleared.
Clearing recently closed tabs works in every browser I've tried, except Orion, so this should definitely be fixed imho.
This is also an issue on the desktop version of Orion btw