Yeah confirmed the bug with the reconcile. The issue is that Gemp is counting how many cards are in your hand, then letting you discard 1, then drawing to fill your hand based on how many it counted before the discard. Because the discard can trigger initiative and other card plays (as we see in the replay above), by the time Gemp refills your hand its count is out of date.
I've added a GitHub issue to track this bug, but considering how much of an edge case it is it might not be fixed for a while.