Trampa 100/250 with Cyc X1 Pro motor

Dear VESC supporter and team,

First of all, I would like to thank you for your work....you are superstars :) !!!!! to everyone participate in the VESC project! Thank You!!!! :)

I use a CYC X1 Pro motor with 100/250....but it doesn't work well in FOC mode....with a 36 volt battery everything is perfect.....but a fully charged 12s or more is problematic. If I reach around 55,000 ERPM under load, the engine starts doing very interesting things (like switching the drive on and off very quickly), without load I reach 80,000 EPRM (and even under less load, if I can pass over 55,000 60,000 ERPM, above  it works fine again)
It works in BLDC mode, I reach 80000 ERPM without load, but under load PWM mode Synchronous only 70000 ERPM max but no realy powerfull... but in PWM mode Bipolar is amazingly strong, but only 55-60000 ......ERPM max....

Another error is: sometimes the motor doesn't start, I have to turn the motor shaft a bit by hand and then it starts... (it only doesn't do this in BLDC PWMbipolar mode)

Can anyone help me with the FOC settings? or to reach a higher RPM in BLDC mode?

Thanks!

A.