Same here it randomly rejects my sideboarding options, but if it happens in my case it usually prevents sideboarding during all subsequent parts of the Bo3. It either happens after game 1 or not at all.
I just lost to this bug once again in my decider match right before mythic ... super fun especially as my matchup would have actually heavily favored me after sideboarding in my control options...
Same here it randomly rejects my sideboarding options, but if it happens in my case it usually prevents sideboarding during all subsequent parts of the Bo3. It either happens after game 1 or not at all.
I just lost to this bug once again in my decider match right before mythic ... super fun especially as my matchup would have actually heavily favored me after sideboarding in my control options...