I think it might be related to jegantha

Issue is still occurring on iOS. Opponent could clearly sideboard, made playing sucky.

this issue persists also in PC version of MTG Arena. Is there a fix for this already? The bug makes Arena so annoying to play!

same, i hope they fix it soon. between explorer bo3 games, after sideboarding and clicking on done, it takes me back again on sideboard screen and i can't do anything at all except to wait until the timer runs out and the game starts again...without the sideboard cards.

me, too. and actually, this issue had begun from the time bloombrow released!

I also have had this issue, before the update and now again. I only get to play every so often and now it is just frustrating, especially when your opponent can sideboard.

I'm also having this issue. This occurs playing multiple different decks. Every time during sideboard I will click continue to finish sideboarding, then the game glitches out and the screen flash one time and the entire sideboard cards disappears and the deck reverts to the original state. After that the continue button no longer works. I would Alt F4 out of the game and rejoin the game, then you can see all of the cards in the sideboard but you can no longer click on them. Now your options are to hit continue and proceed to game 2 and game 3 without sideboarding. This bug honestly makes MTGA a joke.

It has been almost a month since the first report of this and it is all bo3 not just Standard. Makes best of 3 on iOS impossible to enjoy.

I find I can't add cards to my deck from my sideboard after disconnecting in the middle of the previous game and coming back in. This is entirely consistent and started after the release of bloomburrow. I can remove cards but not add.

I have also had this problem, and it persisted after closing arena on the iPad and launching it on my phone for the same match. (iOS)

Same here, since Bloomburrow update, I can't submit my sideboard changes, the "Done" button doesn't work.
If I restart the client (before the end of the sideboarding time), I come to the same screen, but can't click any of the sideboard cards).

The following things don’t help:

- Rotating screen
- Changing deck layout
- Closing and restarting app
- Expanding deck layout

If you remove a card from your deck in second sideboard you just have to wait for timeout because the deck is now below 60 and cards can’t be added, as described above.

Suggest renaming this issue to “iOS Sideboard Broken” or similar for easier discovery