@gochurchgo I wasn't familiar with that Love album but listening to it on streaming it is easy to see how that guitar could quickly become irritating. I don't listen to that kind of music but I have had other preamps that produces what I call glare in that same frequency band. It would only happen on 10-15% of the tracks I played but I couldn't stand it and I ended up selling that gear. Sadly, all I can tell you is I'm not hearing that with my Spinstage. Assuming you like everything else about it I would return the unit and get another one. @lewm's suggestion that there might be a faulty part effecting the RIAA curve is plausible to me.
Also, I think the Lino C only takes balanced inputs. No idea if your turntable supports that but it has stopped me from trying one.