unitProduction is an attribute related to a territory that specifies the number of units that can be produced at a factory in that territory.

You need to add another item to the xml called unitProduction. That is the number of units that factory can produce, if you haven't set it- it defaults to zero and they are displayed as damaged. Newly built factories go through a different process whereby their unitProduction is set to the territorie's production value.

<option name="unitProduction" value="4"/>