There’s no way to know for sure currently but it’s probably not related to Osiris. Considering this scan looks like it’s something created by the Vex, or at least related to them, it’s more likely to be connecting to something made by the Vex. Whatever it’s connecting to is not on Mercury itself but on the far side of the Sun, and as far as I’m aware there’s no info currently available suggesting Osiris would have been in that area. Nor is there any other mentions of something on the far side of the Sun. We may find out more info about it in the future, but for now it looks like this is one of the scans that brings up something mysterious and interesting but doesn’t really offer any concrete info on it.