If you try and use certain actions the action loses sync with what is being selected. This happens a lot. If people don't realize what is going on it can be extremely frustrating. Here is an example. If I am Wyll and I select action bar, hex, then I try and use the d pad to choose between level I or level II, then hit A to select it, the action will switch often and Wyll will execute a move or another attack instead of Hex. This happens a lot. When it does it completely messes up your turn and can lead to a party wipe.
Another quirk on Stadia is that for some of my spells which can be cast as a level I or level II spell I see 5 or 6 copies of it in the dialog window where you choose between level I or level II. For example, hex shows up 6 times as a level II, but never even shows me a level I option.
When playing on Stadia with a controller and you go to your Journal, then select the tips menu, if you are using the D pad to move up and down between items things work as intended, but if you use the left stick to move up and down between items your character will continue to move in game. So..... you can be trying to find out more about stealth and accidentally walk into a bad situation.
I know PC players make up the majority of early access, but I think it would be good if the Larian QA team did a playthrough with Stadia and used the controller. There are many many quirks which players have had to work around since launch. We need a little love on the Stadia side of things.
