mmm - tricky to give precise advice... its wrapped up in learnt memory mapping with experience
Yes happened on 3 occasions all early on in learning process.
Kite never stayed in the air. twice had to actively get the board to go up to get to surface when being dragged underwater..
All times higher end of the wind range for local area so around 20 knots. Gusty site.
Edit - missed pasting this bit in..
Leading edge down and windfull sail getting dragged. yukk.
Worked hard on limiting opportunity my input is along the lines of trying to avoid it occuring..
Each time I tried to stay on board beyond balance point, the easier one went over mostly sideways, the 2 tougher ones arse over and launched the foil. All times I was going slow, In trying to describe it I feel the effort to stay on meant my body was not being flexible or capable of absorbing energy so legs locked straight totally setup to fall off a cliff once overbalanced
So primarily think relates to back foot position and maybe for some also having the foil too far fwd in track when learning.
The default learnt memory response for other kite boarding options (TT or Surf Boards) is back foot pressure for foiling you need to limit or just not do this - the unlearning takes sometime.
I made a comment in the scrum cap post below this one along the lines....
The way you leave the board when foiling is key. ... I 95%+ go over front or back still. Once or twice very gentle drops over side onto foil - a wetsuit helps here. Probably foot straps change this a lot. I always have had one on the front but rarely at the back. Never fight hard to stay balanced - until U pick up that alignment feel (like a continuation of the mast!!).
Take home..
1). If use straps, then check and move position of back one or mast till at least centered over mast. My preference which is where I place feet at take-off now is to have my back foot at the front of the mast. The thinking here is marginally behind the centre of lift for your foil but not way behind.
2). There is a need for speed - not flat out, but for me associating stability and safety with slow did not help.
3). Body stance, so although not easy to be relaxed try to stay crouched in a pro-active stance. Standing and waiting to react is very natural but don't. A useful reset is to put board back down on the surface.
4). Imagine your body is a continuation of the foil mast. If U are out of whack too much chances are early on in the learning curve you perceive this and respond too late and end up fighting for a lost cause. Try to bail before you end up overloading on one foot especially the back one.
Cheers
AP