Drones flipping during flight. Motor problems?


Today, we were flying two quad-copters and they both flipped while in the air.

They both used a drone-kit program to launch and rotate while in the air.

Flight Controller: mRo Control Zero H7
Firmware Version: 4.0.7
GPS: mRo Location One
Frame/Motor/Propeller: Lynxmotion HQuad500
Power module: mRo Power Zero
Battery: Venom 50C 4S 3600mAh 14.8V LiPo
ESC: Lynxmotion 12A Multirotor ESC 1A BEC
Motor: Brushless Rotor Motor 1000Kv 15A

The program works well on 4 other identical quads.

We believe it is either a motor or ESC issue. Below we provide the motor output graphs. Are there any likely causes to our problem that we can check?

Drone 3 full flight

Drone 3’s first flight went well. During the second flight, we had a flip while in guided mode. This can be seen below.

During the third flight for Drone 3, it can be seen that motors 1 and 2 were at different levels than motors 3 and 4.

Drone 4 full flight

In Drone 4’s first flight, it flipped then stabilized itself. The motor output values were also oscillating during the flight.

Drone 4’s second flight also had the same problems as the first flight.

Below, you can find the logs for the above mentioned flights on Dropbox:

Thank you.