Shuffled decks added to unshuffled decks are unshuffled

I discovered this working with the Spirit Island mod, but I suspect it should be duplicatable anywhere that you have shuffled decks added to an unshuffled deck. For reference, in Spirit Island, you have three stacks of “Invader” cards that need to be shuffled and then added to a deck in order, so that you get your Tier 1 cards, followed by your Tier 2 cards, followed by your Tier 3 cards, but with each tier shuffled.

This was implemented by having three decks, which can be “included” to a main deck to draw from. The individual decks are set to re-shuffle “always”, while the main deck is set re-shuffle “never” (because if it were set to re-shuffle, the cards wouldn’t be drawn in tiers). However, what happens here is that while the individual decks are shuffled (you can draw cards and look at them and they appear to be random) but once they are included in the main deck, they are always drawn in the same order (the order in which they are defined in the editor.). You can “fix” this by manually removing cards from each “tier” deck and then putting them back, which seems to change the “order” around - but simply pulling a card out from each deck is not enough to change the order, it seems like something needs to be added back to alter it. It seems like a deck set to re-shuffle “always” should also re-shuffle (internally) when Included to a new deck, even if the new deck is NOT set to shuffle?