Found another bug, though this might be an oversight if anything.
In transmutation, if you fuse two cards, then leave the fused card there, put two new cards in the fuse slots, and then click the already fused card with no valid position to place it, you soft lock because you can't put down the card where you took it and there's nowhere to put it. Only solution is to press escape and lose all that progress.
Loving the game so far though!