That last spacer should not make contact with the frame at all. The compression happens with the metal pass-thru washer that's resting against the top bearing at the head tube. Either that pass thru washer should be thinner by .5mm or that final plastic spacer should have a deeper well to cover more of the pass thru washer as per the last pic
That is what I am expecting, too. As said, I am new to internal cable routing and I might have made a mistake but this looks strange. Had already funny pictures in my head what I could have done wrong with the washer or the bearing
Ideally, I will disassemble the headset today and double-check.
@Sakizashi: The "grinding paste" is a fair point. Especially if the gap remains as seen on the pictures, regular checking of the headset unit will be necessary. I would not have used grease on lower parts of the bike anyway. Stem and handlebars were my main thought.
