Erratic pitch and roll of quad after switched to land flight mode after completion of mission

ArduCopter Copter 4.0
1

Hello everyone,
We have got a problem while doing a mission with cube black FC and T-motor M 1000. The drone started a pretty scary erratic movement in pitch and roll axis on switching to ‘land’ flight mode after completion of an autonomous mission. I request the fellow pilots, developers and enthusiastic community to please help us to find the error. I am attaching the flight log and the video of HUD from mission planner for reference (google drive link attached).

Update: As pointed out by Mr. Dave, I have uploaded the .bin flight log in the same google drive. (Thanks Dave)

https://drive.google.com/drive/folders/1nitypMNe9GRM5Q9-i7kPVVzZfwVc8We8

Screenshot (94)
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2

Need the .bin flight log. Tlogs/Rlogs are not of much use. And the Auto Analysis tool is long out of date.

3

Dear Dave, I have added the .bin flight log for this particular flight in that google drive link. Thanks for the help.