I've also been having this problem with my personal LCG, it comes up often enough because anti-mill is meant to be something you can build your deck around. There are literally fieldstates where you can return cards from your discard to the bottom of deck every turn. Forgetting card positions in a TCG seems like a really core issue with the engine that Trevor should fix. I've also noticed issues with trying to put cards back in specific positions (Scry effects).