Is flickering from glare node normal?

I didn’t see any annoying flickering when I stepped through it frame by frame in the viewport, but in the final render I get massive bright crisp stars in places that they did not exist in the viewport.

Also flickering from fog glow and bloom.

That is not normal. I would guess that you have parts where single pixels vary heavily in brightness from one frame to anorher, like fireflies.
You can not see them because they are inside the a reflection or light source which is supposed to be white.

Haave you tested the offending pixels?