I have owned many matte alligator bags, and I have not seen this (but it looks inherent to the hide).So, I don’t think it is a matter of concern or quality control. (In the sense that I believe it would have been noted and deemed acceptable for top grade). My (non-Hermes) custom Duret Buffalo Dalmatian bag was sourced from three Hermes hides that he purchased, and he and I picked. (Duret was H trained, and the individual who made my bag herself trained H artisans). My hide had two diagonal marks but was still considered by Hermes and by Duret to be top or premier quality.
Of course, if this bothers you, you should bring it up to your SA, but I kind of would like the idea that my alligator bag is extra unique. I do suspect though that my opinion will be the vast minority one on TPF, and most will not agree with me. This is a stock pic from Duret, but it is my specific, actual bag (my bag was the first ever that he made from Buffalo Dalmatian) and he certainly had a choice of the entirety of three hides to choose from. I was in Paris and saw the three hides. You can clearly see two diagonal marks on the top flap (there was no attempt to hide the marks; in fact, Duret chose to show case them)
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ETA: I also love veining on togo leather