I've removed the offending wingtip. It was a RIGHT wingtip. There's no doubt about that. The rear 1/2 to 1/3 was not properly aligned for some reason. Checking my build records, this was the wing that gave me such heartburn when trying to install the aileron. The front half and lower rear half was bonded in with Redux/Araldite. The upper rear half was just epoxy/fiberglass.