Crash : autotune gives very low P-gain on roll axis


first of all my config :

  • 3DR Pixhawk mounted with foams
  • Quadcopter S500 frame (equivalent of F450 but stiffer arms)
  • T-Motor MS2216-9 and Graupner E-Prop 9-5"
  • 400g 4S 3700 LiPo under the frame, aligned with the forward axis
  • HK F-30A ESC flashed SimonK

I fly with this configuration since a couple of months now and I made the PID tuning manually, which gives good results. I had to lower the default roll and pitch P-gains as my copter is slightly overpowered.
After that, I updated to 3.3rc10 and tried autotune functionality, with no wind. It seemed to be a success as all axis were twitching. I saved the new PIDs into the EEProm according to the online doc.
Then I tried to take-off again but it rolled slowly while taking-off until a soft upside-down crash. I tried a second time with the same result.

Going back home, I looked at the log. I saw that all the Pitch values (P, D, ATC_accel) were almost good and close to the ones I found manually, but all the Roll values (P, (D), ATC_accel) where way to low to allow the copter to fly (rate_rll_P~0.02, rate_rll_D=0.004 the minimum allowed value, ATC_accel_R~36000). Yaw values were better than the ones I found manually.

Here is the log file of the autotune fly.
Here is the parameter file were you can find all values after the autotune fly.

Does anybody have an idea ?