First, the Psyker Buffs or Blessings dont apply their selected Mastery bonuses that belong to the "Psychic Combat" Passive tree( the purple colored ones)

This has been tested with "Endurance", "Warp Speed",  "Fiery Form" and "Misfortune" blessings, and with the "Speed Boost" and "Damage Boost" Mastery bonus.

(all of the blessings were tried in sets of 3, considering that a player can only have 3 active).

Second, the perk "Psychic Sequence" is not working aplying its stacks, the current perk descripcion is this one:

-6% Cooldown Reduction to Psychic Powers after using a Phychic Power

Lasts 10 seconds

Stacks up to 5 times (30% Cooldown Reduction)

Currently it doesnt matter if you have 1 or 5 Stacks, it will always give just 6% cooldown reduction, the adicional stacks bring no benefits.

As a side note, this was noticed with a character that has 2.4% cooldown reduction and 8% Cooldown Reduction for skills generating Warp Heat, so its not a problem of the character cooldown reduction hitting the cap.