laiz I only recently started to use Orion on the iPhone. The tab groups setup and work just fine. I didn’t pay attention to the version numbers till now, but I’m guessing I was on 20 the first time and setup the groups.
I usually do a daily refresh of the App Store and update whatever is available that day. So I upgraded and saw my groups were gone. Strange. Well I’ll just recreate because I’m new to this browser and hadn’t created a bunch and could go through history to restore.
Yesterday I saw the 22 version and the notice about the bug, so I happily downloaded it and they were all removed again.
So the moves to 21 and now 22 have deleted the tab groups so far. I will say I mostly spend my time in the general/default group. So not sure if that’s a factor. I never tried having a website opened in one of the tab groups and then updating to see if that would have survived then.
Hope it helps and good luck! It really is just great groups, be in the default group, update app, and poof, they disappear.