2002 S60 Turn signal replacement

[duckpond]

I am replacing my passenger-side turn signal, but I can't replace the turn signal socket into the headlight assembly. It will slide into the assembly but it won't rotate in either direction. It was also hard to remove in the first place.

On the driver's side however, it easily comes out and is easily repositioned.

I then noticed that the driver's side parts look slightly different. Pictures of the passenger side here here

Did anybody have similar issues? Does my car have incompatible parts?