WoodenShipsIronMen Return to Deck broken

In the Wooden Ships and Iron Men module
each side has a log window with two decks with one card each.
The cards are to be dragged around (log window or map) and cloned.
When I use “Return to Deck” on them some do return there,
but some return to a deck where they are not supposed to go.
I tried to edit the module and reassign “Return to Deck” in its properties
to the correct deck, but to no avail.

Any hints ? Does “Return to Deck” work consistently in other modules ?

Thanks in advance, Matthias

So I got an explanation.
The module is too old to work with a new vassal version.
Details in this post:

Thanks for everybodys’ interest, Matthias.