Oil leak 3.0 TDI FLs

Hello, on my A5 with a 3.0 TDI (245 hp, CKVC engine, 2015, 120,000 km), there's quite a bit of oil leaking on both sides, underneath the cylinder heads. As far as I can tell, it's (hopefully only) coming from the supports (also called "tensioning claws") for the injectors (see pictures). There are apparently two (identical?) seals per cylinder (part number 059103631D). Not only are these seals expensive, but they also seem to be of poor quality. No one has ever worked on this engine, so it can't be due to incorrect previous work; it's original like this.
Online, I find very little information on this topic, other than that the seals may not have been replaced during previous work, which could be causing problems.
What are people's experiences like? Are new, genuine seals better than the old, genuine ones? Or better yet, from a reputable supplier specializing in accessories?

Hello,

I would verschandeln the area with brake cleaner to better identify the exact source.
Blowing baby powder (talc) after cleaning may also be helpful.

Best regards, Rainer.