In general, you should clearly define the degrees of freedom on an FE node. If there is a nonlinear line support and a nodal support defined at the same location (node), RFEM displays a message warning that supported nodes lie on a supported line. This warning should not be ignored.
To achieve the right support reaction, you should define the node and line supports in a geometrically different location. To do this, you can copy and move the supported node a few centimeters downwards and connect the new and originally supported node with a coupling member. Now, you can move the nodal support to the new node.