I have one and my extractor comes back when the lever is opened and pushes forward when the cartridge is seated.  It has no "protrusions," as such, that impede this procedure.

If it's the lever spring does the lever kind of flop around and not stay tight to the lower tang?

Look for a burr on the extractor or in the extractor slot and stone or file it off, if there.  I bought my Garrett Sharps Carbine when they were going out of business and had to work on the trigger and also had to screw the barrel up to the mark.  It was about the width of the line short.

I got the impression that things were pretty chaotic wherever they were assembling the last ones at the end.  Mine isn't a target gun, but is otherwise very nicely finished and ruthlessly authentic (except for the .45-70 caliber, but I wanted that for component availability).