A bit of both. Sometimes it is behind, which is definitely an issue. But even if it's in front, it can be a bit hard to see for a couple of reasons.
The arrow has a white outline, and a some cats have a lot of white on them, so it blends a bit.
The arrow points to the head, and when you have a bunch of long cats entangled it gets a bit confusing which parts actually belong to the active cat.
The clearest for me I think would be to change outline of the entire cat, or something like that.