Much to my surprise - it seems like the culprit was a 1.5kg mock payload that we were using to test the aircraft’s flight with the estimate payload we will have onboard. Replacing the payload with another 1.5kg mock payload seemed to fix vibrations. Don’t know why the initial mock payload of two random vices was causing vibrations - must have somehow been rattling around (although they were strapped in pretty tight). Regardless - glad its not a structural issue.
One side note - it seems like there is still some clipping even tho vibes were pretty low from my point of view. Any thoughts on this? I was really flying pretty aggressively to see if vibes were looking good - so maybe that is it?
https://drive.google.com/drive/folders/12QNM9FPOnc6Ub47J-FI9iLNG39iAUg-4?usp=sharing