By way of full disclosure, I am not the most skilled pilot, and today I tried something I shouldn't have tried, and I wanted to share. I was shooting with my GoPro just for kicks. My CS8 had my 5D Mark III on the 2-axis gimbal. After a successful flight, I tried to come back and land on the picnic table from which I had launched it, because I was at the beach and I figured I'd be able to avoid getting a bunch of sand blowing around. I'm not 100% sure what happened. I've watched the video frame by frame, and it just looks like it bounced funny, and I may have overcorrected. But the good news is that there was no damage to any of the parts. I deliberately leave a small amount of slack in all by boom clamps (on both the frame and the gimbal), so instead of maybe breaking, a bunch of things just moved around. I blew out all the sand, straightened a bunch of things, put on 2 new batteries, and I was back in the air in about 15 minutes. Amazing. Thank you to FreeFly and to Andy, whose instructions I consider divinely inspired. Please do not share this video beyond this forum. Thank you!
It could also be the problem of differential "ground" (well, table) effect. You've got one boom out over the side of the table and the rest on the table, so there is differential push-back from the "ground." The other possibility is that the airflow over the table allowed a wind gust to get under the prop that's not over the table and you got differential lift. Or both. Thanks for the attempt to elevate me beyond my station in life, but I still put my trousers on one leg at time. Do understand that Google spiders this forum so if you search for appropriate keywords, the world will see this video. Andy.