Interesting, I tried that scenario with fresh setup for both 8.4.x and 8.5.x
...

Interesting, I tried that scenario with fresh setup for both 8.4.x and 8.5.x
Maybe, I might have missed something while doing a fresh setup.

I had two different setups so I didn't need to run composer to update things.
Anyway, we should think about some upgrade path to prevent these kinds of issues like update hooks etc.