Unexpected behavior using "currentProperty.isValueAllowed"

Summary:

I am not getting the expected results from currentProperty.isValueAllowed - am I using it incorrectly?

Content (please ensure you mask any confidential information):

I've got one of those cases where staring at something for too long results in it all becoming gibberish, so I need a simple sanity check — I'm not sure if I've confused Expression Builder by using the same property name in multiple places, if I'm running into issues due to the use of node-type properties, if I've just got bad syntax, or something else. Clearer perspectives welcome!

I have these dimensions:

1. Dimension Employee contains various properties, including the internal ID as a simple string (