desert carbon
On 6/11 snapshot, Player 1 has exiled [[Misthollow Griffin]] from Player 2's hand via [[Elite Spellbinder]]. Player 2 can cast the Griffin from exile, and should have a choice of whether to do so via the Spellbinder's ability or via the Griffin, and Forge recognizes this properly.
However, no matter which option Player 2 chooses, they're prompted to pay 4UU, the cost with the Spellbinder tax, when they should be able to cast it for 2UU via the Griffin's ability, as they would want to do almost every time.
teal carbon
more to cast.