So, I posted this on the Starfinder2e subreddit, but I will post it here as well to make sure it is seen:
I wrote:
RESTORATIVE RECOLLECTION [one-action]
ANCHORING CONCENTRATE WITCHWARPER
Frequency once per round
Despite being stunned, there is a part of your mind in another reality still processing your situation. Decrease your stunned value by 2 or slowed value by 1. If you already lost an action this turn due to that condition, you can Recall Knowledge with any skill you are trained in.
And the stunned condition: https://2e.aonprd.com/Conditions.aspx?ID=93
Stunned states that you cannot act, and the duration/action reductions only occur when your turn begins and you would normally regain actions. I was initially thinking that this would be useful if you became stunned on your turn, but stunned makes you completely unable to act! If you became stunned on your turn, your turn would immediately end!
So, my next thought was to check the playtest errata, and there's nothing regarding the witchwarper in it at all.
Please, someone tell me I'm misunderstanding about the stunned condition, or there's some other value to this part of the action, but as far as I understand it, decreasing your stunned value with it is not possible because
If you became stunned on your turn, you cannot act and your turn ends
If your next turn begins and you are able to act, at all, you no longer have the stunned condition anyway.
To be clear, the rest of the action is fine, and I get the value of it, but I can't see a situation where decreasing your stunned condition with this action is possible.