Question:
For a support that can only transfer compressive forces, tensile forces are also displayed. How is this possible?
Answer:
In a result combination of your model, load cases that act alternatively ("or") are connected in such a way that they act positively once and negatively once. Negative factors in an RC can be problematic if the calculation is nonlinear: The failure of springs, tension members, and so on, then acts in the "wrong" direction and provides the corresponding results.
The RC results are combined from the existing results: if a support has compressive forces in a load case, the value is converted by the minus sign in the combination criterion and applied as a tensile force.
Remedy: Define the load cases that should act negatively in the combination criterion as new load cases with a negative load.