Custom Overlay affecting transparency of other mod overlays

I'm creating a mod that should be used with a mod that another person has created, when I create a GUI or an overlay for some reason it messes with the transparency of all overlays. 
For example, I have an overlay that is supposed to be semi-transparent (it's for a blindness effect on the player), and when I load the dev client it works fine:

However, when I drop the mod into a folder with the other mod I want it to be used with (also made in MCreator), it completely messes it up:

I was able to get it to work before when I had a few overlays, and then I decided to add some GUIs to test. The GUIs messed up the transparency in the dev client so I deleted them, but the problem still appears. When I searched in the forum I found the post by Kemuri that said to change .HELMET to .TEXT, I did that to every overlay and still the problem occurs.