I created a predicate to detect when the player is looking at a Villager with a specific tag.

Here's how you could replicate the error:

IMAGE 1 = Works fine when the villager is not in contact with any blocks.
(Red circle shows that the F3 panel correctly detects that I am looking at a villager)
(Green circle: Flame particles work only when the predicate is detected as true)

IMAGE 2 = But, when I put a block on his head, and point anywhere in his hitbox, the predicate stops working even though I am looking at him.
(The red circle shows that the F3 panel detects that I AM looking at the villager)
(Green circle: no more particles. Predicate is false)

IMAGE 3 = If the stone block is not on his head but on his body, the predicate DOES work.

BONUS IMAGE 4 = Also, for some reason, when I look at the stone block while that stone block is on his body, the predicate is TRUE, BUT, the F3 panel doesn't detect that I'm looking at the villager.