What’s going on here?

This is my trusty 2016 Canyon Ultimate CF SL7.

Primarily my Winter or backup bike now. However, recently had a new rear mech and 11-34t fitted by a LBS I don't normally use as I'm using it for Lands End to John o'Groats later this year. The extra gear will be useful for some of the steeper climbs we will have and the old mech was shot.

Anyway, I took it out on a 100 mile spin on Monday. Just making sure all was ok. 65miles in managed to split the inside plate off one of the chain links. Chain held together but was shifting horribly of course. Found a bike shop a few miles later (very lucky).

Sorted a chain etc. but told me the rear mech is on all wrong. Wouldn't elaborate though. Especially as really, it's been shifting through gears ok.

Anyway, 10 miles later and a flat tyre showed that something was dreadfully wrong.

Flipped the bike as I always do. Shifted into the small cog, loosened the quick release. Then when pushing the derailleur to disengage the chain, it moved inwards thus preventing me from taking the wheel out. I had to remove the axle and twist the wheel at an angle to get it out. Literally had about 1mm clearance.

So, before I take it back to the LBS, what on earth have they done?

Oh, and that cassette and chain were spotless before a short test spin today. Fenwick lube picks up so much crap, even when it's just ok the rollers. 🤷