You need to leave it until "all" the moisture has left the mortar.
This is at your discretion.
With all the litigation on products and workmanship these days manufacturers and applicators are very reluctant to advise or specify which can often be over or beyond what seems sensible because of fear of litigation.
The litigation has pushed up the price and specification of many things because when your in court and its cost you a motza the discretion of the court is merciless in what it deems practical.
I have some tradie mates who have just spent $14000 to have a ruling thrown out of court.
They dont have the money for that kind of thing. One has left the industry.
Because there is so many grey areas with employment, safety and product on items that may be for incidence deemed to be as safe as practical you will see a lot less recommendation and higher prices to cover risk and litigation.
Its really just starting to accelerate in some states so expect little advice in some states.
Yes I dribbled on but you can see why I said use your discretion.
Currently obsessed with non-hydraulic mortars