That still holds true but there are things you need to check and procedures to go through before you condemn the BOB.

If it's just missed steps while in use and not when things turn on like Vacuum or Spindle etc, which could be electrical noise, the first thing to check is the mechanicals.
It doesn't take much binding to stall a small stepper motor when rapidly moving from position to position so if you have a sticky axis this could be the cause. Try to take note which axis loses steps and whereabouts in the Job it loses steps, ie: Rapid moves, etc.

If the mechanicals is good then it could be that you just have it over tuned and it's close to the edge where torque drops away, but only on certain moves like rapid moves.
An easy test is to just lower the velocity in motor tuning slightly and see if it still loses steps.

What is the velocity and acceleration in Motor tuning for each Axis.?

I would check out the mechanicals first before doing anything else.