it might be an issue but I just don't know sorry. Just wait and see if they are "stuck" to one side of the shell I guess. That is really what turning is for, so they don't attach to the shell. But I would think with it being day 18 and only a few days away from lock down you would be ok.
Like I just mentioned on another thread with someone not turning since day 18- turning is VERY important and if not done correctly can result in deformed ducklings. Leg and facial problems especially common when it comes to external features. If you ducklings are not hatching now- there is a good chance that not turning the eggs since day 18 had a lot to do with it. There are so many other things that can go wrong- especially if the temperature was too low.
In future hatchings Pax y9ou may like to consider the following- - set the duck eggs first - then a week later add the chicken eggs- that way they can all hatch together and no eggs miss out in getting turned.