Ok, that is the joint where the liner comes up and over the transom. It's pretty common to see this. Does this mean it's not an issue? It depends on if water got in there in mass. If your transom is sound, you can grind this joint down to clean glass and use resin with some chopped glass to make a thick peanut butter thickness bondo to fill it in.
If the transom is not sound, then you have to go deeper and at least replace the core, which will involve popping this liner portion anyway.