[Ultimaker 3 doesnt print fully on some Z layers.]

So I have been having a problem with the Ultimaker not printing fully on some of the Z layers. I literally have tried everything that I could find info on for Z related problems. I have cleaned the Z lead screw and bearings, I have cleaning out the motor that pulls the filaments, I have tried slowing down the feed rate of extrusion, I have check all belts. I have tried different models and different filaments. I am lost and cannot figure out how to fix this issue. With printing the same model it happens in different Z locations

 

With the picture provided, it will print perfect then all of a sudden not full print out  Z layers, then it will go back to printing good and then back to missing Z info. 

 

Does anyone have any advice or have dealt with this problem.

 

Thanks

Jasper

 

 

 

[Please Help!!!]

Has this happened to anyone else with their Ultimaker3?  I came into work after the weekend and was suprised with this disaster.

Does anyone know what wouldve caused this?