I'm using the TopologyBuilder with default settings to create linkage in an ESRI sourced water network - mainly because there's no node-to-node connectivity like there is in Oracle.

Generally its working well but has thrown up an anomaly. The transformer has created the edges of a line which should be two adjoining mains at the left and right edge, but instead the left edge is showing as joining to itself.

In the picture the highlighted main should be showing with a left edge of edgid 83360 and the right edge of edge_id 83331. Instead the left edge is 83391 - which is itself:

Any ideas why this is happening? I have used a snapper and GeometryValidator and there appears to be no issues with the geometry. Do I need to add a tolerance into the TopologyBuilder?

Many thanks in advance!