I've had it happen in several of my Tikkas. Not a stuck bolt, but a tight-to-open bolt.

And yes, it's a reliable sign…in fact, you're way past safe when it happens.

I've had a sticky bolt on hot loads and even had the extractor blow off of one.

The smoothness is deceiving so once you notice the sticky bolt, definitely dial back the load.  For smaller calibers, definitely do not go above max book load as the pressure curves build faster and are less linear than larger capacity rounds.