Sorry should have been more specific...

Riding in chop and slipping out, my guess is that you are riding a stiff board. Stiff boards are very fast in flat water and will pop for unhooked tricks like a springboard... but in the chop you can easily start "skipping" from wave tip to wave tip (like a shell skips across the surface of a lake when you throw it jut right)... this means your fins are only in the water briefly and if you are edging, you are going to slip out and fall.

I'm familiar with this because at 195lbs I ride a lot of stiff boards for that extra pop.

The only option here is SLOW DOWN. How? Dig the board hard upwind, drag your butt like a dog with a dirty rear (this one is considered poor style but we all do it when we have to), or stand up and haul straight down wind at your kite.

Btw, if you just bear off a little you will speed up, if but if you go straight at your kite you will slow down as the kite stalls.

Riding in chop takes technique no matter what board you are on but generally softer tips or a LOT of concave (maco) will help considerably but at some cost... soft tips (usually) reduce pop, and lots of concave makes it hard to release the edge and butter slide. There are of course compromises by making the board really stiff in the middle and soft at the very end of the tips for both pop and flex (the flexifoil and nobile are this sort of design... and it's a good one).

Hope this helps.