Custom monster bug
 

Fiendish Blessing isn't adding CHA bonus to AC. Is this a community pack thing, or is it a bug to report to Lone Wolf?

Community File: COM_5ePack_PHB - Monsters

The one you are using within the custom monster race is called raFienBles. This come's from Lone Wolf. I can see it doesn't have an Eval Script on it so it's not really doing anything. Not really surprising if this was used on a monster as the stat block probably already had the bonus built in.

You can tell this btw by enabling Data File Debugging in the Develop menu of Hero Lab. From there you can right click things and see their name. In this case the name does not have '5C' in it indicating this is controlled by LWD.

This has finally taught me how to add custom Special Traits to the Special Traits menu within the Custom Monster Race though.

Need to add the following tag to the special trait and it will appear in the list.

Group ID: Universal
Tag ID: Universal
Name: Universal Monster Ability
Abbrev: Universal Monster Ability