So here is the response from Tomas:

"This is more of a design issue than a bug. What happens is that in this variant, you roll 4 dice and then move the corresponding pieces (1=pawn, 2=knight, etc). However, the dice can roll a piece that cannot move at all, and then you have to skip that move. I think that this is fine and just a result of randomness (+you can always try to keep a move open for all your piece types). But I can see the argument from the other side as well - it sad to get a bad roll and be able to move less pieces."