Is there a reason for a jet liner to raise the nose wheel early during the take-off run?
It's a 727 take-off technique used on unpaved surfaces.

Glimpse of the real deal here.

Possibly an old-timer was showing someone how it was done. Or someone was doing a recurrent for it.

It's to avoid nose gear damage if it hit a rock, or damage to other parts if said rock/debris were to be deflected. Also to avoid digging the nose gear into the soft field—reducing the rolling friction.