I was using an elytra(this probably doesn't affect anything but also a turtle helmet) and flew into some water I switched to f5 mode and went downwards quickly and it gave me the error invalid move player packet received

1:get an elytra
2: fly into water and hold ctrl
3: move around a bit (if you do it immediately it doesn't work(probably just me but holding f5 down seemed to decrease the amount of time it took for this to happen))
I flew downwards originally but I have gotten it by flying upwards