Answer:
The program interprets the entered model for calculation in an FE mesh. This mesh depends on the shape parameters set in the "FE Mesh" dialog box.
To correct any modeling inaccuracies, the parameter ε is available in the FE mesh settings. In a figurative sense, it regulates the maximum distance between the FE nodes. If the distance between the elements / nodes in the model is smaller than the parameter ε, the FE nodes are merged. This merging then results in the described "connection" of the members in the calculation.
You can avoid this effect and simulate the members independently by setting the parameter ε to be less than the available distance.