Ah, interesting! That fixed it. Thank you. So Cura actually checks if vertices are connected in an object, and if not, it prints topologically separate parts separately like this? I assumed it would essentially just voxelize each object and then slice them as if they had been solid all along.
My model has small overhanging / bridge type sections near a wall. They should be perfectly printable with continuous wall paths, but Cura (3.6.0) creates a loop path in mid air instead. Is there a way to correct this behavior?