I think I have a similar problem (bug?), but I have 2 movements instead and I'd like to do the first part of the Z move...but it tells me I can't
I'm in attitude A with a ship of the line, so I have 3 movements, reduced to 2 as I lost a row of rigging. So I'd like to spend my two moves by turning into attitude C and moving forward once (as this is the only way I can try to reach the enemies left).
However, after turning into attitude C it says "Cannot move that fast" when I try to move forward.

GameID 74 , about every move after 40..probably tried it even earlier