Periscope texture or resolution bug?

[Halogen]

Recently when playing the game both periscopes on the left side can be seen through to the outside of the boat (See where my mouse cursor is)
I thought it was some resolution bug but it doesn't seem like it is
I'm playing my own modded version of Onealex if that helps

Here is the screenshot I took, note where the cursor is you can see the cargo ship https://ibb.co/8r7GnR5