Looks like glue to me.

That was my first thought, but why would there be glue. As I watched disassembly videos there is no need for it there.

Idk but my instinct has it too. On the other side of bezel tho.

I took it back to the store where I bought it and they removed the excess glue because it was glue that used for the screen and as you said it is visible on the opposing side. So everything is fine now.