It's not a deterministic bug where I can easily post steps to reproduce. It happens randomly.
For this video I opened 4 websites in this profile (bravado.de, audd.io, lanaboards.com, news.ycombinator.com), and then closed / opened the profile and scrolled a bit around. See the massive freezes.
Here Orion starts to freeze when clicking on a thread. The second freeze happens when I quit the profile with CMD+Q.
Here the freeze happens when I click on the other tabs after a fresh profile start. This is not my internet connection being slow. On Bravado the browser also freezes during scrolling.
All of this behaviour never happened with the previous version.
Edit: Here also a crash report I got on closing Orion, I don't know if it's related to my issue: https://paste.debian.net/plainh/332e81fa