xy_sled_parts.stl reported as non-manifold by stl_normalize.py

[mjparme]

When make runs stl_normalize.py on xy_sled_parts.stl the script fails because it reports it as non-manifold. This appears harmless because it is succesfully rendered, just whatever that python script does doesn't get done to xy_sled_parts.stl (I just restarted make and since make saw it already did that file it dutifully just did the ones it hadn't done yet). This was from the v3.1 branch.

./stl_normalize.py -c STLs/xy_sled_parts.stl -o STLs/xy_sled_parts.stl
NON-MANIFOLD DUPLICATE FACE! STLs/xy_sled_parts.stl: [39.589, 14.059, 20.399] - [43.859, 14.059, 13.002] - [43.859, 14.07, 13.002]
NON-MANIFOLD DUPLICATE FACE! STLs/xy_sled_parts.stl: [-30.411, 14.059, 20.399] - [-26.14, 14.07, 13.002] - [-30.413, 14.07, 20.402]
NON-MANIFOLD DUPLICATE FACE! STLs/xy_sled_parts.stl: [39.589, 14.059, 20.399] - [43.859, 14.07, 13.002] - [39.587, 14.07, 20.402]
NON-MANIFOLD DUPLICATE FACE! STLs/xy_sled_parts.stl: [29.589, 14.059, 20.399] - [33.859, 14.07, 13.002] - [29.587, 14.07, 20.402]
NON-MANIFOLD DUPLICATE FACE! STLs/xy_sled_parts.stl: [-10.411, 14.059, 20.399] - [-6.141, 14.07, 13.002] - [-10.413, 14.07, 20.402]
NON-MANIFOLD DUPLICATE FACE! STLs/xy_sled_parts.stl: [-40.411, 14.059, 20.399] - [-36.141, 14.059, 13.002] - [-36.141, 14.07, 13.002]
NON-MANIFOLD DUPLICATE FACE! STLs/xy_sled_parts.stl: [-20.411, 14.059, 20.399] - [-16.14, 14.07, 13.002] - [-20.413, 14.07, 20.402]
NON-MANIFOLD DUPLICATE FACE! STLs/xy_sled_parts.stl: [-10.411, 14.059, 20.399] - [-6.141, 14.059, 13.002] - [-6.141, 14.07, 13.002]
NON-MANIFOLD DUPLICATE FACE! STLs/xy_sled_parts.stl: [19.589, 14.059, 20.399] - [23.86, 14.07, 13.002] - [19.587, 14.07, 20.402]
NON-MANIFOLD DUPLICATE FACE! STLs/xy_sled_parts.stl: [-40.411, 14.059, 20.399] - [-36.141, 14.07, 13.002] - [-40.413, 14.07, 20.402]
NON-MANIFOLD DUPLICATE FACE! STLs/xy_sled_parts.stl: [9.589, 14.059, 20.399] - [13.86, 14.07, 13.002] - [9.587, 14.07, 20.402]
NON-MANIFOLD DUPLICATE FACE! STLs/xy_sled_parts.stl: [-0.411, 14.059, 20.399] - [3.86, 14.07, 13.002] - [-0.413, 14.07, 20.402]
NON-MANIFOLD DUPLICATE FACE! STLs/xy_sled_parts.stl: [29.589, 14.059, 20.399] - [33.859, 14.059, 13.002] - [33.859, 14.07, 13.002]
NON-MANIFOLD DUPLICATE EDGE! STLs/xy_sled_parts.stl: [9.589, 14.059, 20.399] - [13.86, 14.07, 13.002]
NON-MANIFOLD DUPLICATE EDGE! STLs/xy_sled_parts.stl: [-30.411, 14.059, 20.399] - [-30.413, 14.07, 20.402]
NON-MANIFOLD DUPLICATE EDGE! STLs/xy_sled_parts.stl: [19.589, 14.059, 20.399] - [23.86, 14.07, 13.002]
NON-MANIFOLD DUPLICATE EDGE! STLs/xy_sled_parts.stl: [43.859, 14.059, 12.977] - [39.542, 14.059, 5.5]
NON-MANIFOLD DUPLICATE EDGE! STLs/xy_sled_parts.stl: [29.589, 14.059, 20.399] - [33.859, 14.059, 13.002]
NON-MANIFOLD DUPLICATE EDGE! STLs/xy_sled_parts.stl: [19.589, 14.059, 20.399] - [19.587, 14.07, 20.402]
NON-MANIFOLD DUPLICATE EDGE! STLs/xy_sled_parts.stl: [39.589, 14.059, 20.399] - [39.587, 14.07, 20.402]
NON-MANIFOLD DUPLICATE EDGE! STLs/xy_sled_parts.stl: [-40.411, 14.059, 20.399] - [-36.141, 14.059, 13.002]
NON-MANIFOLD DUPLICATE EDGE! STLs/xy_sled_parts.stl: [-36.141, 14.059, 12.977] - [-40.458, 14.059, 5.5]
NON-MANIFOLD DUPLICATE EDGE! STLs/xy_sled_parts.stl: [39.589, 14.059, 20.399] - [43.859, 14.07, 13.002]
NON-MANIFOLD DUPLICATE EDGE! STLs/xy_sled_parts.stl: [-10.411, 14.059, 20.399] - [-6.141, 14.07, 13.002]
NON-MANIFOLD DUPLICATE EDGE! STLs/xy_sled_parts.stl: [-6.141, 14.059, 12.977] - [-10.458, 14.059, 5.5]
NON-MANIFOLD DUPLICATE EDGE! STLs/xy_sled_parts.stl: [-40.411, 14.059, 20.399] - [-40.413, 14.07, 20.402]
NON-MANIFOLD DUPLICATE EDGE! STLs/xy_sled_parts.stl: [-20.411, 14.059, 20.399] - [-20.413, 14.07, 20.402]
NON-MANIFOLD DUPLICATE EDGE! STLs/xy_sled_parts.stl: [-0.411, 14.059, 20.399] - [-0.413, 14.07, 20.402]
NON-MANIFOLD DUPLICATE EDGE! STLs/xy_sled_parts.stl: [33.859, 14.059, 12.977] - [29.542, 14.059, 5.5]
NON-MANIFOLD DUPLICATE EDGE! STLs/xy_sled_parts.stl: [-0.411, 14.059, 20.399] - [3.86, 14.07, 13.002]
NON-MANIFOLD DUPLICATE EDGE! STLs/xy_sled_parts.stl: [-20.411, 14.059, 20.399] - [-16.14, 14.07, 13.002]
NON-MANIFOLD DUPLICATE EDGE! STLs/xy_sled_parts.stl: [39.589, 14.059, 20.399] - [43.859, 14.059, 13.002]
NON-MANIFOLD DUPLICATE EDGE! STLs/xy_sled_parts.stl: [-10.411, 14.059, 20.399] - [-6.141, 14.059, 13.002]
NON-MANIFOLD DUPLICATE EDGE! STLs/xy_sled_parts.stl: [9.589, 14.059, 20.399] - [9.587, 14.07, 20.402]
NON-MANIFOLD DUPLICATE EDGE! STLs/xy_sled_parts.stl: [-30.411, 14.059, 20.399] - [-26.14, 14.07, 13.002]
NON-MANIFOLD DUPLICATE EDGE! STLs/xy_sled_parts.stl: [29.589, 14.059, 20.399] - [29.587, 14.07, 20.402]
NON-MANIFOLD DUPLICATE EDGE! STLs/xy_sled_parts.stl: [-40.411, 14.059, 20.399] - [-36.141, 14.07, 13.002]
NON-MANIFOLD DUPLICATE EDGE! STLs/xy_sled_parts.stl: [29.589, 14.059, 20.399] - [33.859, 14.07, 13.002]
NON-MANIFOLD DUPLICATE EDGE! STLs/xy_sled_parts.stl: [-10.411, 14.059, 20.399] - [-10.413, 14.07, 20.402]
make: *** [STLs/xy_sled_parts.stl] Error 255

[ManuGithubSteam]

Hi I think that are harmless warnings, i had them to but the part was renderd and did slice fine with Prusa Slicer. However the slicer repaired some stuff but it printed fine and works.

Maybe openscad should continue with warnings to fix this ?