Btw, I see that you are an Ansys employee - can you tell me the reason why the joint reaction doesn't appear if loaded by joint condition but once loaded by RD, the reaction is there? In both cases, the forces are present in the system (as demonstrated by the test by force loading in my 1st post). Not to mention that mixing remote displacements with joints seems prone to error (over constraint).
I do several projects in Rigid Dynamics per year and almost every time I experience some strange behaviour like this which is really frustrating to debug for complex models. So any inside view could really help me to understand better what things are to be avoided when using the Rigid Dynamics module.