To help out the original poster: I think this is the same bug I posted here: https://forum.vassalengine.org/t/send-to-functions-bug-after-viewing-2-consecutive-logs/5887/1
I’m guessing that the issue isn’t which player is active.
The reason it isn’t being reproduced is because it depends on a player loading 2+ consecutive logs posted by other players. After doing so, all ‘send to’ functions break and pieces get sent to 0,0 instead of their destination decks.
If the OP could try the following two tests it could confirm/refute my theory:
Load any log/save, then return a card to a deck (no problem)
As player 3, try loading a log from player 1, stepping through it, loading a log from player 2 as a continuation, stepping through it then returning a card to a deck (it will be sent to 0,0)