I have just spent the afternoon changing the left-hand tailgate light cluster on my 2018 Sportbrake and thought I would share the process as I was unable to find relevant information before I started.
Knowing how the chrome strip attaches would have saved me a couple of hours working out to get it off.
(If anyone can advise how to resize images I would be grateful as the all go in full width here).

1. With the tailgate up, open the warning triangle storage compartment and remove the two screws (Torx or flathead screwdriver required).
   
2. Use fingers to pull down the plastic liner, starting at the top of the tailgate.
   NOTE: there are three wires inside so make sure to support the cover.
   
3. Disconnect the boot close switch and the two lights by pushing in the tiny latch in and sliding the connector apart.
   
4. Put the cover to one side.
   
5. Disconnect the plug from the light cluster and undo the three nuts holding the light cluster in place (8mm spanner or socket required).
   
   
   
6. There are six clips across the chrome strip. I was only changing the left-hand light cluster so didn’t need to remove the strip from the right-hand cluster.
   
   
   
   
   
7. Partially close the tailgate. The chrome strip is held on with spring clips and foam double sided tape.
   
   
   
8. Use a cable tie or piece of wire to carefully unstick the double sided tape. Alternate this with gently prising the chrome strip away from the light cluster and tailgate (I used a trim clip removal tool).
   Take care not to crack the light cluster or damage the paintwork.
   
9. Once the chrome strip is free, the light-cluster should lift out. Install the new light cluster, fit the three nuts and re-connect the plug.
   
10. At this stage it is a good idea to check the light works before putting everything back together.
    
11. Clean the old double sided tape off the tailgate with your thumb (I didn’t bother with the back of the chrome strip), wash down both surfaces and allow to dry before fitting new tape.

 

I'll add the Topix page for it just for fun, although your pictures look better.

Interestingly, they assume you remove and throw away the chrome strip and install a new one, due to the tape. Seems wasteful but I'm not surprised. Not a lot of sportbrakes in our market anyway, I've only ever worked on 2 or 3.

BTW, warranty time is .3, so 18 minutes start to finish. This is why techs hate doing warranty work.

 

Thank you for adding the Topix document. It would have been so useful doing this job. I'm assuming it is an industry document, not available to joe public.
I can see why they replace the trim, it would be very easy to damage. If you were just ripping it off and fitting a new one, that could easily save 10mins. Even so 30mins would be a more realistic timeframe.

 

It's from the workshop manual, there are copies available out there for download and the online manual can be accessed by anyone with a subscription, but in general yes it's not readily available outside dealerships.