Very interesting - I've never seen anything like that. It appears to have been temporary IMU failure of some kind. Also, the attitude data from the DAT are different from the txt log shown above which is unusual. According to the DAT file, which is pretty definitive on these things, it wasn't rolling but actually did seven full back flips - while climbing:
View attachment 105609
The direct cause is clear - the motors were responsible of course, but why the FC was doing that is not clear:
View attachment 105610
The event stream indicates multiple control failures, none of which shed any further light on the problem. It may have been a computational failure rather than hardware.
1.221 : 1257 [L-FLYMODE][Ctrl<5>] REQ_APP AUTO_TAKEOFF ctrl_auto_takeoff
2.919 : 1342 [L-FMU/FSM]not near ground
3.417 : 1366 [L-NS][AHRS]height max obv num [3/16]
3.577 : 1374 [L-NS][AHRS] yaw aligned 1
4.064 : 1399 [L-FDI][CTRL] tilt ctrl failed when takeoff,75.0 deg
4.064 : 1399 [L-FDI][CTRL]: fault on , takeoff_fail
4.084 : 1400 [L-FDI][CTRL] tilt ctrl failed when takeoff,75.0 deg
...
5.023 : 1447 [L-FDI][CTRL]: fault off, takeoff_fail
5.680 : 1480 [L-FDI]NS(0) GPS(0): fault off, abrupt
6.242 : 1508 [L-FLYMODE]CTRL reset all by auto take off lanch fail
6.263 : 1509 [L-FLYMODE][Ctrl<1>] REQ_RC_NORMAL ATTI ctrl_atti
7.683 : 1580 [L-FDI][CTRL] tilt ctrl failed when takeoff,75.0 deg
...
8.382 : 1615 [L-NS] [AHRS] gyro mag inconsist on
8.680 : 1630 [L-FDI]NS(0) GPS(0): fault on , abrupt
8.879 : 1640 [L-FDI]NS(0) GPS(0): fault off, abrupt
10.122 : 1702 [L-NS][AHRS] gyro mag inconsist off
10.304 : 1711 [L-FDI][CTRL] tilt ctrl failed when takeoff,75.0 deg
10.304 : 1711 [L-FDI][CTRL]: fault on , takeoff_fail
10.323 : 1712 [L-FDI][CTRL] tilt ctrl failed when takeoff,75.0 deg
... etc.