setting a rotation for a rotator with c-v connected activator blocks interferes with the rail movement detection.
when moving a docked entity onto a rotator all connected activators do get swithced to on and thereby disabling the set rotation value.
placing the button or activator next to the rotator detects the movement jsut fine in my tests.
disabling the c-v linked movement detection for rotator rail blocks seems to be the fastest fix for that problem.