Gitlab UI showing old version of files in a branch

I have a project with multiple branches. When I browse through the files in the branches via Gitlab UI, master branch is showing 2 year old files. When I checkout master branch in my local machine, it shows the latest files. When I create a new branch from master via Gitlab UI, the new branch is created with this old version files.

What might be the issue? Any option to troubleshoot this?

This is probably a silly question, but is your “default branch” set correctly in your project settings? (Settings → Repository, I think).