OK, Got the image working. I read the thread linked, and I think my problem is similar, but not quite the same. the wall I'm trying to print is simply too narrow for three perimeters to be printed. Again, the wall thickness is 1.27mm and I have a 0.5mm nozzle. I've tried fixing this with one perimeter (second picture) and three perimeters, but the problem still persists. If infill were to be inside this wall, the overlap would be >50%, so the thin wall infill feature won't trigger. My customer is adamant that I use this wall thickness, so I can't change it.
Any other suggestions on how I can get around this?
Original problem (3 perimeters):
The problem still persists (1 perimeter):