The Mana Reservation Efficiency mastery has been replaced as there is now a much larger amount of Mana Reservation Efficiency for Curse Auras on the passive tree." (The mastery was 30%) :
Passive Skill Tree Guide for Beginners - Path of Exile - Maxroll.gg
Path of Exile 2.6.0 | How to level as Low Life RF - YouTube
Steam Community :: Guide :: Beginner's Guide To Make Your Own Build ... v1.3
POE 3.20: How Can I Do My Spark Inquisitor On 1 Divine Orb Budget?
Bug Reports - Corrupted jewel mana reservation does nothing - Forum - Path of Exile
Bug Reports - Determination Mana Reservation Mastery and Blood Magic - Forum - Path of Exile
Trial of the Ancestors League Mechanic Guide (PoE Trial of the Ancestors 3.22) - PoE Vault