I've had this happen a few times. I flip the kite over and it sits there totally luffing; pulling either lines doesn't seem to get it tracking to either side. Then as the pattern goes, wind gets under the LE and rolls it. Fortunately yesterday it relaunched hot inside out then flipped right side.

I put it down to too little wind in the past, but it was 20 knots when it happened yesterday. Mysterious. This has only happened to me in the last year, like a new virus.

Any ideas on what I can do

Thanks

Try pulling (tugging)on 1 frontline and as soon as kite turns (twists), pull on opposite side rear line and kite should relaunch as usual. Takes some practice ,but works ( for me ) quite well.