John Citizen
I am tempted to point out post #2 but that's a bit like putting my hand on the flap lever before your call..
Very relevant when selecting Flap 1 but not Flap 0, on a heavy aircraft S speed is close to Flap auto-retract speed. In high (sic) turbulence at max weight auto-retract will probably happen as you accelerate, due to speed fluctuations - all as designed and you still have the slats working for you. The trick is to stay below VFE until the flaps are retracted - the VMAX tape moves to a higher speed when the flaps
start to retract.
And to take retire2015's point a little further, on a turbulent day this is a good subject to include in the T/O brief - that way the PNF is already in the loop from the start.