Does it go on one of your connections? And then the body or something would press the connection firmly with no chamce of it coming off ? Just a guess but makes the most sense to me D
I have a Mavic with its top off sitting on my workbench. Looking inside, I don't see anything that looks exactly like that. The closest thing I see is this pad on the ESC:
I think the one you have is to big to be a pad from the front sensor ribbon cables: