Styles NOT updating across multiple files in a book

Greetings,

The problem:

I've created an Object Style called DiagramXY (which mainly modifies the X,Y position of the object) present in multiple INDD files in a book, but I've noticed that if I use Synchronize Book, it only FULLY updates the object to the DiagramXY style's new X,Y coordinates, if the layer with the object was UNLOCKED prior to syncing. For files that use the DiagramXY on a LOCKED layer object, the style only updates the DiagramXY values, but shows up as DiagramXY+ on the object, which I am able to see after unlocking the layer. If I press Alt+click on the object's DiagramXY+, the object will then correctly update to the new/correct X,Y position and now as DiagramXY. 

The question:

If I want to synchornize styles correcty across mulitple files in a Book, do the layers NEED to be UNLOCKED? Is there a setting to lock layers, but still allow for Style syncing?

Thanks for any clarity on this 🙂