Opacity and collision problems

I have a simple collision set up. The weird thing that's never happened to me is that when the opacity of the sprite is too low (somewhere between 0 and 3) all the walls on the left start acting weird. It's not a serious issue because there are a few ways around it, but I'm just curious about what's going on. I'm not sure if it's a bug or not.

video - https://drive.google.com/file/d/1K4v6KRWV9yTK0C9aPOxZw1yjh5fJQkgC/view?usp=sharing