I think I found a bug with deck hotkeys in saved games in Vassal 3.5.4
I have a draw deck and a discard deck. When the draw deck empties, it sends a hotkey to the discard deck and that transfers the discards back to the draw deck.
This works fine as long as the game has not been saved. If I load a saved game, the draw deck either fails to send a hotkey to the discard deck of the discard deck is ignoring it as the discards do not transfer.
To test this, I manually transferred all but one card to the discard deck. I then saved the game. Before closing, I had a player draw the last remaining card and the discards transferred over correctly. I then closed and loaded the saved game. When I had a player draw the last remaining, no discard transfer occurred.