Hello Patrick,
Thank you for your answer,
This ESC came from warranty with default settings, anyway I tried to reset it dozen of times with different firmware versions, with 2-4-6S, brushless/brushed mode, ... Have done all it could be done with settings unfortunately...
Something is certainly wrong on hardware and it's probably linked to this BEC shunted I talked about below... Just badluck

, there is no deadman (only this one bad thing among 3 motors (2 1515/1y and 1 1520/1y) and 3 ESCs), I have MMv3 backups anyway. Just wanted to know if someone has already had the same issue...
I will contact the support team. Thanks for your reactivity.
Nuz69