Did it help?
It’s certainly a tough object with the super thin wing tissue. But you say you’ve had luck before.
The areas also include some parts of the frame, so the thickness might not be the issue.
What puzzles me is that the “missing” areas are all but one irregularly cross-shaped. Looks like you painted them on, is that so?
What color did you use, if true? Is it possible that it’s so uniform that RC doesn’t find enough features?
Are you certain that the areas are actually missing or do they just have a significantly lower density?