here is work around

t1 = diag_tickTime;
p1 = position player;
onEachFrame {
_speed = ((position player) distance p1) / (diag_tickTime - t1);
t1 = diag_tickTime;
p1 = position player;
hint parsetext format ["speed player<br/>%1", _speed];
};

The thing is this measures actual speed in m/s the speed command seems to measure imaginary speed and in km/h? A bit odd considering everything in the game is metres and seconds.

You should use time instead of diag_tickTime, and try handle division by zero errors ;) otherwise your speed won't be exact to ingame speed

just to confirm velocityModelSpace suffers the same problem

velocity of projectile's x & y stays frozen from their initial value, z appears to update correctly.

fixed, somewhere in between 2013-2016