Germany's GGL Merkblatt for virtual slot permissions, read with §22a(8) of the GlüStV, prohibits a game design in which the multiple of the stake paid as a win varies during the course of the game. The win must be a multiple fixed before the round begins.
A rising free-spins multiplier ladder is exactly that. So is a collector harvest. Its payout is the number of collectors times the sum of the coins, and collectors keep landing during the respins, so the multiple a coin will eventually pay is not fixed when the round starts.
So the pack itself marks two of our games as not permitted in that market, and the server refuses every launch of them there without anybody having to remember. The flag flips when somebody has an answer instead of an inference.
We also think it is worth publishing what is not the reason. Our third game has four fixed jackpots, and the obvious guess is that the Jackpotverbot in §22a(8) sentence 2 catches it. It probably does not: those jackpots are fixed multiples of the stake, not a pool built from other players' stakes. We recorded that in the migration, so the next person to work on the collector question does not have to work out the jackpot half again.