I'm new to Cura so bear with me as I try and describe this problem, hopefully the pictures will help.
When the print gets to the point that it is building a top layer it does not put a continuous border around the layer causing the layer ends to drop into the infill voids.
It seems to me that it should print a continuous border before starting the layer fill so that the ends of the layer can attach to the border.
Does this make sense?
Thanks