Is re-analyzing normal after upgrading to 1.3? [Yes]

Yep. That’s normal.

As nice as it is to have analysis completed it’s not required to use Roon. If you play a track that hasn’t been analyzed yet then that track is done on-demand before it’s played.

If you bump analysis down to 2 cores when you want to play music the dropouts should stop. You can always up it again when you aren’t playing.