Same problem.

Same problem. For some reason it seems to think I can select standard decks but all my friendly brawl decks say 3 invalid cards. If I click on edit deck then the game seems to think they are now standard decks and now cards are marked as being the invalid ones. If I do pick a standard deck then it changes it mind and says those decks are now invalid.

This has been an issue since "Patch - 2021.08.10"

Please work on this bug. I mainly play MTG Arena with my friends more than I do the online play, so it sucks not being able to play brawl with my friend at all due to this deck selection issue.

Please give an update. This problem is from a month ago and still not working properly!

I am also having the friendly brawl challenge issue. All "Brawl" and "Friendly Brawl" decks become locked on the deck selection screen of the challenge, stating that they all have 3 invalid cards. When attempting to edit one of these decks, such as change it's format, the format list is frozen on standard, despite the deck being a brawl deck. During the Friendly Brawl challenge the only deck that allows itself to be selected is my one "standard" deck, selecting this deck results in the game stating that it is invalid.

This has been happening since about a week or so. Before that I used to challenge my friends for brawl matches regularly, but now we cannot select our decks any more after challenging each other. Affects all Brawl gamemodes.

Can still play Brawl against random people, but I'd rather play with my friends sometimes.

I have this but it's extended to standard brawl as well.