We had a car that developed a 'catch' in the steering when driving. It was as though the steering wheel was stuck in a momentary detent. It did not interfere with safe driving.
I examined the power steering fluid. It had tiny metal particles in it. I suspected there was grinding occurring somewhere in the steering mechanism.
We had the car inspected. I forget if I mentioned the sticky steering. Anyway the mechanic said it needed a new rack-and-pinion.