@bramus It seems like the abrupt transition in Chrome is caused by the Stylish extension. But in Safari TP’s case, it’s just how it works: there’s no green background anywhere in styles. It seems like it comes from the hero picture.
https://github.com/pepelsbey/pepelsbey.dev/blob/main/src/styles/global/transitions.css
@pepelsbey Also noticed Safari Technology Preview flashes a color in the background when doing a View Transition.
I have filed https://bugs.webkit.org/show_bug.cgi?id=279962 for that a while ago.
As for Chrome: I tried your site and the first 4 times it showed no transition but after that all was fine. Maybe it was a caching issue? Trying it out with DevTools set to no cache and slow 3G I still see the VTs.