2012 Buick Verano AC compressor noise

2012 Buick Verano
39K miles
2.4L L4

So around 2 weeks ago I had the ac compressor replaced under warranty because it was making a whining noise that changed with the rpms. When I got the car back the whining noise was still present but not as noticeable inside the cabin. I figured it must be normal. Well because of the obsessive person I am I have been examining all the noises on my car. I’ve noticed that when the ac compressor comes on there is like a hard buzzing noise that pulses a few times then stops, I have also noticed this when I come to a stop at a red light occasionally. Now I am not sure if this noise was present with the old compressor because I usually had the radio on and this noise can only be heard with the fan down low and the radio off. I could barley here it in the engine bay. I know these noises are coming from the compressor because I have used a stethoscope on it and heard them. To be honest I am not sure if the ac whined before the first replacement because i bought the car in the winter so it wasn’t being used then. Part of me feels like I am paranoid but another part of me says don’t ignore it. Just wondering if anyone had any thoughts, am I being ridiculous? I know its inevitable that it will make some noise but I’m just confused.