Hi 2hanssen4u and welcome on this board.
i checked this case on a surface pro in fl studio, with everything up to date.
We had an issue with the buchla easel v in FL studio on first release ( cables were disappearing when using detached mode in FL studio)
it is now ok using buchla easel v 1.0.3.1268.
You can check if your synths are up to date ,if you open Arturia software center, while connected to the internet.
Hope this helps,
best,