I think this functionality is no more :(
GitLab changed the way it presents Compare revisions view by adding some new features.
Therefore old method for automatic file scroll using #SHA is no more.

I noticed in Gitlab version GitLab Enterprise Edition 18.3.0-pre 9aa8f0e5c6d
You can easily notice whether you have this feature in Code -> Compare revisions view by seeing this file browser. Does anyone has a way around it?