My tags are not being detected by Look At Rotator

The min/max ranges are set correctly, the tag names are chosen from a list, everything is in order, but on the signals tab the 'target found' simply does not light up.

Other tags are working - I have a follower rig that correctly follows a tag on my model. This rig has two tags on either end that the model should turn toward when given input, these are the tags that aren't being detected.

Am I missing anything obvious in some other settings?