Question 7500f burnmark?

[LZR]

Hello there, after extraction cpu from the socket i saw that mark. Is this a burnmark? I haven't seen this mark when i received CPU, it's possible what it was already there. I haven't done extreme overcloking, my max temps were around 100 and max voltage 1.35 for one start(during stress tests), maybe for 15-25 mins, could it happen because of this? I tried to clean it with cloth and isopropyl alcohol but seems like it gives no results, CPU works fine tho but i just wanna know what is it, it'd be pretty disappointing to have burnmark on brand new CPU, also if it's a burn mark I'm afraid it's possible what new mark will appear right on the contacts in the future, maybe i should apply for warranty? (I have b650m mortar wifi if it matters)

https://imgur.com/a/DmWQmRI