Update branch from main disregarding changes I've made

I’m working in a branch and have made a lot of edits. Normally I update from main every now and then to get things up to date and to get rid of the popup, but when I did it today I see that the page I’m working on is changed when opening the dialog. The preview in “Keep branch” is reflecting this and showing me an older version.

In the background I can see that the view shifts into the “Version history” view which is very strange.

It’s driving me mad. Please help