Mana cost of skills and reservation bug since 3.19

Since the drop of 3.19 I got random bugs on my mana reserving auras and mana cost of skills. Sometimes I can reserve all of my auras (dropped one of them after the patch since the reservation mastery is gone), sometimes game deactivates 2 of them right after login on entering hideout.

Similary sometimes my 6-linked Spark costs 2 mana (as it is supposed to be) and entering a map it jumps to something like 43 mana per cast.

This makes the game literally unplayable, relogging does not always solve the problem and even if it works the map is bricked and since I stack auras I need the auras and since i only have like ~60 mana unreserved I can't play with a casting cost of 43 mana with over 8 casts per second (hideout) and no form of mana leech...

Edit: Mana reservation issue seems to affect mostly my Divergent Tempest Shield. Can't activate it while wearing a shield, even if i deactivate ALL my other auras.
Having 125 of 787 mana unreserved while it has a reservation cost of 9,47%, which equals to ~75 mana that it SHOULD reserve.

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tobiasbott2 wrote:

Similary sometimes my 6-linked Spark costs 2 mana (as it is supposed to be) and entering a map it jumps to something like 43 mana per cast.

https://www.pathofexile.com/forum/view-thread/3295483
There are other threads on Mageblood not behaving properly. You're likely seeing the "reduced mana costs during flask effect" on your Basalt Flask not applying.

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tobiasbott2 wrote:

Edit: Mana reservation issue seems to affect mostly my Divergent Tempest Shield. Can't activate it while wearing a shield, even if i deactivate ALL my other auras.
Having 125 of 787 mana unreserved while it has a reservation cost of 9,47%, which equals to ~75 mana that it SHOULD reserve.

https://www.pathofexile.com/forum/view-thread/3296389
If you can't activate the aura when you have enough unreserved mana, and especially if you have no unreserved mana with no supports linked to the gem, you may not meet the requirements to activate the aura in the first place.

First suspect would be the shield not counting as equipped, or something like Necromantic Aegis. However, the thread linked above suggested that an equipped pet mtx interfered with being able to activate the skill. Try checking if something similar is inhibiting your ability to activate Tempest Shield.