Odd normals on the hinge

Hello, I was going about fixing my normals when I stumbled accross this. I cant seem to find any way to fix it but I do believe it has something to do with the mirror modifiers. Can anyone explain what is happening here? Thank you very much in advance.

as you can see here it looks a lot when you have two meshes in the same spot, but I tried merging vertices by distance and it said there were no vertices removed, so I'm stumped as to what is causing this mess. 

  • I think you are absolutely right that it's a Mirror issue: you have a Mirror on the X- and Z- axis, That should probably be only the X. Then it is followed by another Mirror Modifier, but I don't know what that one is doing...

    Because the Mirror is not changing the position of the Vertices in Edit Mode (it's a Modifier!), Merging the Vertices won't work.