I'm seeing embedded UI mod updates, but not stat updates (tested on commander energy generation with existing and pasted commander)
Maybe it only effects units you build after the mod data has been updated? Like it might copy the specific values from the blueprint to the unit on creation of the unit.
Yep, that's what it does. That's what we use to to test miniscule changes we make to balance. It's great because it means I don't have to restart my game every two minutes.