Despite that seam bubble appearing to actually be from the manufacturing process, I also wouldn’t trust this tank… it’s got questionable silicone work in other areas visible in the photo, which would lead me to believe this tank isn’t from a major manufacturer…
The tank is a drop down tank from IM... Discontinued for years (4ish) My LFS has a few left over that he is selling for $800. It is only a 20g tank.
$50, a razor blade and a $14 tube of aquarium sealant... done...
But, because it is only a 20g and the affected area at the top, you would probably be good as is.
But it is a nice foray into tank repair...
my 2cents