Proximal Tangibility Bug

On the Gates of Halani map, between the first and second gate, I have run into a group of monsters with the proximal tangibility tag. They will not come out of the ethereal state, even when standing in the midst of them. They can still do damage to me.

After running away from their spawn point, they have reverted to acting normal.

This happened to me as well. Thought I was going crazy.