If you zoom up close and are close to the ground, the camera's pivot point is basically off screen, and rotating the camera becomes very unintuitive, because you're not really orbiting what is at the center of the screen. If you're not zoomed-in that close, it becomes less of an issue, but is still noticeable. If you use Tweaks++ mod, which allows you to zoom in even further, then this issue is amplified.
Make the camera orbit what you see!
Edit: It seems this is an issue with Tweaks++ when "ground clipping" is disabled. So, never mind.
I guess then the suggestion becomes: Let me zoom in more, so I don't need a mod that will let me do this. Sometimes you need to dig in really close to single out that one pipe you're working on from a spaghetti of pipes...