Whether or not there exist a pressure thrust from the expansion joint to the piping is strictly a function of the design of the expansion joint.

Most metallic expansion joints will supply some thrust, and some designs will reduce this.

Most flexible expansion joints will not supply a meaningful load onto piping and equipment, so long as you're operating within the expansion joint's operating limits.

I believe you would be incorrect to assert that they will always impart a thrust as it's not out of the realm of reason for a design to have an effectively negative Poisson ratio and actually impart tension onto the piping connections; this is precisely how each of the muscles in your body work.