If you switch back to scirocco, check the behavior of the commoner, which takes on its line.
The behavior seems an unexpected empty promotion on his line.
To reproduce: Cf1-e4 d8-d7 2. Ce4xd7 Guc8-c7 3. Cd7xe10=Sq+
Where did you test this? For the version I build from the latest version in pullreq I just see a Squirrel appear. And I don't know what you mean by 'takes on a line'. In that same version the Commoner for me just moves like a King.
Where did you test this? For the version I build from the latest version in pullreq I just see a Squirrel appear. And I don't know what you mean by 'takes on a line'. In that same version the Commoner for me just moves like a King.