Lack of enthrallment in SB (spoilers?)

[Vulcwen]

.. The ananta seem still able to reason after the fight, but I don't really believe they're no longer under her influence...

I can just speculate, but perhaps tempering is never permanent by definition in the first place. What if tempering is just the act of messing with someone's emotions and memories for a certain period of time. After a primal is defeated, they have no direct influence anymore, but whatever changes they did to their memories stay.
Ifrit: just completely delete the past, burn it away. Results are permanent, as after they're released, they'd not remember who they were.
Lakshmi: create a dream, feel happy, unlike your past. So after you defeat lakshmi, she has left a memory of the dream, which they'd remember as the happiest moments of their lives, and the WoL being the one to end it, putting them back to misery. However, they do remember what it was like before, and thus still remember who they are.

[SicariusSeven]

I can just speculate, but perhaps tempering is never permanent by definition in the first place. What if tempering is just the act of messing with someone's emotions and memories for a certain period of time. After a primal is defeated, they have no direct influence anymore, but whatever changes they did to their memories stay.

If you do the Amaal'ja beastribe quest you find a Miqo'te who had been 'tempered'. However it seems she was just driven crazy and instead of killing her, they let her go back to live with her old tribe to 'recover'. So maybe being tempered isn't permanent but it more than likely screws someone up mentally.