Hi, I also encounter a problem with the dji mavic mini drone bought 2 weeks ago, namely one of the engines needs 1.2 laps by hand before starting to leave with the others. If I don't do this, the other 3 start a little and they stop, if I turn the 4th engine by hand 1.2 laps and then start the drone it's ok.

Sounds like a problem with the one motor.  As a test, rotate all four motors one by one and compare the feel.  They should all feel the same.  If the motor with the problem feels stiff (or just different), very carefully inspect it for any debris that could be jamming it.  If all four motors feel the same, it sounds like an electrical problem.

Hello there leopescaru. I am sorry for the trouble this has caused and thank you for reaching out. Since this issue is happening on your DJI Mavic Mini, I would recommend you to contact our DJI support team at https://www.dji.com/support?site=brandsite&from=nav for further assistance. We would do their best to find out the reason of the incident and then the corresponding resolution/fix would be provided. Just a reminder that  DJI do not recommend doing a DIY in fixing the said DJI drone to avoid further damaging the said unit and voiding the warranty as well. Thank you.