Surface split sometimes fails and I can’t understand exactly why and how to bypass the issue. In the attached file there are two surfaces which are mirror copies. I try to split them with geodesic lines. One surface splits just fine, the second one is missing one part.
Split Surface Problem.gh (21.5 KB)
If so, it is most likely a tolerance issue. Try to reset your rhino unit’s absolute tolerance from 0.001 to 0.01~0.1 and recompute.
Spot on 
Worked like charm! But wouldn’t that affect the precision?
Even 0.0011 works. It only happens when the value is exactly 0.001.
Well, not sure about the exact reason. Maybe some McNeel guys could explain the reason to you 
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