I'm amazed!!!
It's really funny how Google services' - and now Microsoft's - just keep on failing on Firefox.
Even more amazing is that they take soo many time to fix and never before another one takes it's place.
Now... One could argue that's a result of a different rendering engine... But also funny is that it happens between chrome and edge also, sometimes...
Go figure...
And that's why I keep using Firefox...
I don't quite know what their target audience is, but from my experience businesses (on desktop) primarily use Chromium based browsers, with a few percent of Safari users.
From business perspective, it can be quite reasonable to treat Safari bugs as low-ish priority, and just not dedicate any time to ensure other browsers work correctly. Of course this changes if you also need to support mobile/tablet devices, where iOS/Safari is similarly popular (if not more, depending on the location of your users) to Android/Chromium.
However, they should definitely update documentation, if they don't intent to keep FF support.