It is possible to programmatically register a geometric network feature class as versioned while all other network feature classes remaining unversioned. Using the RegisterAsVersioned method on a single network feature class does not propagate through the geometric network and its participating feature classes.
This mixed environment can lead to inconsistencies in the geometric network.
The recommended use of RegisterAsVersioned is at the feature dataset level rather than at the individual feature class level. This workflow is exposed by default through the user interface in ArcCatalog.
This mixed state can be achieved by using RegisterAsVersioned on a single geometric network feature class as opposed to the feature dataset containing the geometric network.