They can’t.
The freeze bug/missing buttons bug is a known issue and not in any way specific to GAC.
The devs at some point explained a bit more about it, but in essence it isn’t a bug in itself, it is the effect you see of some underlying bug stopping the battle from progressing.
This means that the cause can be quite varied even though what you see is the same, hence why it’s not just a single bug the devs can and should get fixed.
You can go to the support forum and post there details of the battle that got hung up which might help CG identify and fix the underlying issue, but it’s not going to change the battle you have played and it’s not going to prevent future bugs from producing the same missing buttons effect.