Hi 3DS Family

I made a symmetry of a fixture assembly in Assembly design workbench and assemble mirror part on it, it assembles correctly, but when i make a separate assembly and snap all the parts with the Symmetry fixture assembly, the mirror part do not assemble correctly with the concentric constrains and shows a difference of 0.001mm of axis to axis distance. Could you please tell me where is the problem and how can i resolve it?

Best

Amrit