It would seem that glass has the magical properties of X-Ray! :D
If anybody can tell me a way to fix this I would love to hear it, as this problem takes away from the aesthetic of my houses considerably...

WHAT THE HECK IS THAT THING HOW DID YOU DO THAT OMG OMG OMG ?!!!!

well the glass simply is like that, there's no fixing it, and I don't think it is a big deal, i'ts not game breaking after all.

@WhiteFireStone
Those are transparent voxels. There are 9 of them, you can
find the group of 9 on the upper right side of your voxel pallet

If you hold mouth over it it should also give you a pop-up description.
Let me know if that helps :)

Ou... Well... Yes... I think I saw that somewhere... in the Designer...

Thanks, digitalmonkey