Dear Makis, dear Benjamin,
thanks for the hints. The advice to look more into detail at the interfaces was very valuable.
I think I found the problem: The problem occurred already on the CalculiX side: There was a geometry point defined in the middle of disc, which has been meshed but the node had no element connection. The node was stored in the original CalculiX input file but CalculiX seems to skip this node (as it was not used) during initialisation of the simulation. I didn’t find this nodes listed anymore in the *.frd-file. But it seems the adapter still had this node in the list but zero displacement has obviously been reported to this node (as it was not used in FEA). The zero-displacement node has been used in the mapping to the OpenFOAM mesh which seems to cause the sticking points on the mesh faces. So your adapter works well, I have to get rid of the unused nodes.
I just rerun my simulation and it looks fine so far. If there is interest in this case, I can upload it (maybe after getting it working reliably). But it is rather a demonstration case which does not use physical correct properties
Ulrich