
I think your problem is the goats. I recommend chickens, along with burning incense.
I upgraded Resolve Studio from 17 to 19 earlier this week and was never prompted for an activation code, presumably it just used what was already there from 17.
Today, it prompts me for the activation code. I entered it, saw it scrolling through no licenses available, then apparently deleted the least recently used seat, and finally came up as normal. A couple of shutdowns / restarts and I still get no prompt.
I'm posting this mainly to offer corroborating data that sometime in the last 24 hours something seems to have changed in the activation system and affects Resolve as well. Although I didn't have to resort to chickens or goats, it seems like something got broken.