For a Cube Black definitely upgrade to 3.6.12 right away - if not jump right to latest stable, 4.0.3 at the moment. I know the original SB2 recommended 3.6.11 but I think further issues were fixed in .12
Ensure your Mission Planner is updated too.
You’ve already got
WP_YAW_BEHAVIOR,2
which is what I would have suggested - try setting it to 1 or 3 and see if there’s any difference.
https://ardupilot.org/copter/docs/parameters.html#wp-yaw-behavior-yaw-behaviour-during-missions
For the landing/disarming issue all I can see is vibes are bit too high which will be confusing the flight controller and it wont be able to tell you’ve landed. There’s some clipping too.
Try the usual: balance props, check for loose items, secure wiring and all, make sure the FC anti-vibration is not being impeded by wiring rubbing or pulled tight.
I noticed there’s a few other parameters you can fix up too, use this spreadsheet to compare against yours:
MOT_BAT_VOLT* and Battery failsafe jumps out at me.
MOT_SPIN_ARM and MOT_SPIN_MIN are practically the same, maybe increase the MIN value a bit to something like 0.12