Bug: Crash and AI stuck if maximum hand size is negative

[rex4]

If I have "Jin-Gitaxias, Core Augur" twice thanks to Spark Double, my opponent maximum hand size will be -7, and this causes a java crash and AI stuck at "Waiting for opponent" on cleanup. Strangely, if it's my opponent who has those 2 cards, it works fine, it says to discard until I have -7 cards but discarding all my hand works like it should.

More extreme stuff: Freeform Vanguard doesn't directly exist in forge but is possible nonetheless by making a custom dck file, and it that case, game crash if one has that much avatars that hand size is negative already when the game starts. The game also crash at the beginning if you have that much avatars that your maximum hand size is higher than deck size but I don't know what would happen in mtgo in that case (as far as I know vanguard only exist officially in mtgo).