"Your branch is old, Would you like to pull" causing merge conflict

Not sure exact steps to get into this situation, but I had an old PR branch locally, the author added commits, rebased the whole thing onto master, then force pushed. I checked it out, and saw that the files were still in the old state.

I got a notification saying "This branch can be updated" or similar, but when I clicked "pull", I got a bunch of merge conflicts (the old changes conflicting with the new changes, when the new should have directly replaced the old, but didn't probably due to the force-push/rebase).

I ran git pull --abort to get back to the old state, than ran vscode's git sync (which for me does rebase, not sure if thats relevant), and ended up in the correct state. Perhaps the "Pull" button should trigger a git sync? Though that might push bad commits so I'm not sure.