seems like I lost track of this project…
@cjquijano is actually right. What the cyclic symmetry condition does is the following: it works as a bonded contact, but actually bonds t the slave in a rotated coordinate system to the master.
This means that it can still allow the system to rotate around the cyclic symmetry axis if this is not prevented at the master surface.
So what we usually do to prevent this is to add a fixed value condition at the master and fix there the direction which is normal to the master. In some cases you would need to swap master and slave (and change the sign for the rotation axis accordingly) so we use the face which is perpendicular to a coordinate axis as master.
Alternatively we can use a symmetry condition on the master.
I copied Christopher’s project and applied the above changes (additionally I replace the fixed support at the bottom with a fixed value leaving only the axial direction constrained): https://www.simscale.com/workbench/?pid=8247173219304259707&rru=b8c12682-ac90-4c1f-bb6a-3de738fd81dc&ci=29c8ecf9-587e-43c1-a871-841ead00b9d3&ct=SOLUTION_FIELD&mt=SIMULATION_RESULT
The case finished easily in a couple of minutes and the deformation looks fine: