Reveal does...nothing?

[Meowakin]

Magus Renuo Umbra (presumably Reveal) appears to do absolutely nothing when cast. Need more test subjects to confirm, but there's no message and nothing appears to happen even if you know a target is hidden nearby.

[Rex]

This spell is not a simple reveal, it actually checks your magical arcana skill VS the hidden creatures hiding skill, with a few points of randomness.
Double checked and it's working as intended.