Just a guess here but in Breeze v 1.1.3 we added a the EntityInfo.ForceUpdate boolean property but it never made it into the main Breeze documentation, it only appeared in the release notes.
This property may be used to force a server side update of an entire entity when server side modification has been made to any property of an existing entity. The other approach that may be used is to explicitly update the EntityInfo.OriginalValuesMap.
The idea behind both of these is that on an update Breeze only creates an update statement for those se properties that have been changed. Any client side changes are automatically detected because of Breeze's tracking mechanism which adds an entry into an 'originalValuesMap', but this cannot be done automatically for server side changes because the server side entities are not instrumented to perform notification about property changes.