After running Replication Client, users may notice traces stopping at lines that were recently updated on the source SDE geodatabase. Further investigation will show these lines are no longer connected to the rest of the geometric network at one or both ends, and the problem exists in the ServerBase folder's copies of the backdrop as well.
Due to a performance enhancement made for Replication Server at 10.0.3, a faster method of connecting features to the geometric network is used by Replication Server when updating the backdrop. Unfortunately, we have since found that this method does not consistently reconnect existing features whose connectivity is altered due to the addition of new features at their connection points, or from moving the feature to elsewhere in the network.
This issue is fixed in 10.2.1a SP1 patch #1532, as well as 10.2.1b SP1. The former is available now at GIS Downloads, and the latter will be available at the same location in January 2016. Because this change requires using the previous, 'slower but more reliable' method of connecting features to the geometric network, a slight reduction in the performance of Replication Server is expected when updating or adding features that participate in the geometric network.