Why did I get the message "ENDING: The Ruin Accord" saying 'Don't miss out on Power Cores!' when the Milestones don't reward any Power Cores?

The Ruin Accord Milestones award Epic Essence, used for Chapter Boosts, T3 Level 1 Ions, and Basic T3 Iso-8 Orb Fragments.. none of these rewards are Power Cores..

Snippet of message: https://i.imgur.com/PDu6eFe.png

Snippet of Milestone page: https://i.imgur.com/WUyha9Q.png

Bit of a slap in the face considering how restrictive Power Cores have become..