Shimano RD-R7000 cable cut into thread?

Question

1. That gap/cut in the hollow screw of the cable mount is not supposed to be there, right?
2. If so, is this a typical defect?
3. The hollow screw is pressed into the derailleur body and not replaceable, so the whole derailleur needs to be replaced right?

Top image: gap left/top of the cable
Bottom image: gap above the cable

These photos were taken having shifted to the smallest cog. The cable had least tension.

It looks like the cable had sawn its way into the screw.

I've never seen this with other derailleurs.

I was looking for symptoms where the derailleur was stuck on the largest cog. Shifting to smaller cogs would not do anything. The gear would eventually slip into its place.

Discovering this was an epiphany. It would explain the behavior; the cable was stuck and held in place in that gap even though tension on the cable was released by shifting.

This is how that part looks on a product picture:

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More pictures from different angles:

Answer 1

I don't have a new one in front of me, but yes that looks like the cable has sawn through due to the extreme exit angle.

If the barrel adjuster itself is affected, that is easy to replace. The plastic outer part of the RD-R7000 barrel adjuster is different and special looking compared to most Shimano RDs, but I believe the steel threaded adjuster itself within it is the same generic 4-notched type that many rear derailleurs and shifters use, so it should be easy to find even if an official Y3F398030 cable adjuster kit as shown in the exploded view diagram isn't.

For the part of the derailleur itself that has the groove, install one of the long-nosed Shimano 4mm shift housing ferrules. Good shops that work on road bikes should all have this, or you can order them individually or get them as part of any of the current Shimano road cable sets. Jagwire and others have their own version of the same thing, which is fine if that's what you come up with.

Shimano made this aspect of the current generation of road groups very confusing. Most of the 11-speed road rear derailleurs except this one have the "Cover With Tongue" insert (see part number 4 in the link) that prevents rub in this area. This includes the first generation of 11-speed 105 (RD-5800), and also the second generation Ultegra and Dura-Ace (R8000 and R9100), but not R7000 105. I don't believe RD-R7000 has the little recess to add one even if you tried. But, the geometry is the same and it has the same problems with friction in this area that necessitates the insert in the other models. Shimano's literature spells out very clearly to only use the aluminum non-nosed "Sealed Outer Cap" ferrule at the derailleur end of the rear loop (see page 30 of the dealer manual for ST-R7000, with a similar note in the RD-R7000 manual), so you are breaking this rule if you add a nosed ferrule there, but I've see it solve problems like you're having and have never seen much down side. To be clear, you're going to have the nose running down and creating a smoother contact surface, the same way the insert does in RD-R8000 and RD-R9100. Any issues with it are no worse than using common 4mm plastic shift ferrules, which are often used on all kinds of rear derailleurs.