Equipping my epic level 35 Eveline’s Locket only increases my light mastery (as it’s light attuned), and it does it by about 30%. No other masteries receive any bonus.
This is on version 1.3.0.21554
EDIT: As Egara suggested, it is being applied in battle, just not on the character sheet.
I don’t own this gear but there is one question:
did you also check the stats during battle because some are only shown in active mode?
Easiest way is to start a Quick Battle and then tap on the 3-bar symbol at top left. Scroll down and check.
Great question. I did what you suggested, and it does appear to add in battle! So it must be only in active mode. Did not realize that some bonuses would only show in battle.
What’s the reason for some bonuses not being shown on the character sheet? Seems like it would be quite useful to have them all there for playing with builds.
Thanks for the suggestion and info!
@Malumos I agree - it would be more helpful if it showed on the character screen, especially for those static bonuses. Having said that, there WAS a bug in which the applied bonus was not consistent with the gear level (epic, legendary, mythic, etc.). You should double check that you’re getting the correct percentage boost in battle!
I checked and it’s correctly adding 9% to all masteries. Thank you! 
Hey!
Thank you for bringing this up. I’ve raised with the development team that Eveline’s Locket isn’t applying the bonus to the character sheet and they have let me know that this is intended.
Eveline’s Locket is designed to only apply the stat bonuses when in battle. I have provided feedback to the devs about this not being in the items description so it can updated to reflect this.
Thank you again for letting us know, it’s greatly appreciated
OminousGMan - Support Human 