I think I found the cause at least for my case:
The use of a "Camera Mapping (WSM)" modifier in the scene causes the problem.
I used that modifier on a mesh that TyFlow was relating to in a tyflow "Mapping" operator. Interestingly, even after deleting the "Mapping" operator in TyFlow (so the camera mapped object became officially unrelated to Tyflow) the problem remained until I switched off the camera mapping modifier completely.
The use of a "Camera Mapping (WSM)" modifier in the scene causes the problem.
I used that modifier on a mesh that TyFlow was relating to in a tyflow "Mapping" operator. Interestingly, even after deleting the "Mapping" operator in TyFlow (so the camera mapped object became officially unrelated to Tyflow) the problem remained until I switched off the camera mapping modifier completely.