When building a geometric network, an edge feature does not snap, even though it is within the snapping tolerance. If the length of the edge feature is less than the snapping tolerance, it cannot be snapped since it will collapse into a point creating an invalid feature. To prevent this, the feature is removed from consideration during snapping.
This issue can be resolved in two ways:
1. Rebuild your network with a smaller snapping tolerance. The snapping tolerance specified for building a network should not be larger than any of the edge features participating in the network.
2. Prior to or after building your network, determine which edge features are smaller than the snapping tolerance and manually adjust their geometries to the desired result.