Bug/Issue Issue With Mk 1 And Mk 2 Coaches Not Being Compatible With Each Other Each Other

This is a issue I've being having with the brand new formation designer feature. I have tried to make some mix Br mk 1 and mk 2 coach formations but I've had trouble making it. As when I have a rake of Mk2 coaches and then try to add a mk 1 coach from SOS it only shows up in the placing menu if a Mk1 BG or BSO has already been placed. When I try deleting or moving the coaches around to see if they work they won't move or have the delete button. I personally believe this is due to both coaches having different braking though I don't know if this is the main cause because nothing indicates the coaches aren't compatible but somehow WSR mk 1 coaches work with Mk 2s which is weird. If you have any ideas to help me fix the issue or once the formation designer is no longer in beta this is addressed to improve the quality of the designer it would be greatly appreciated.