The issue with UCS set to matching anything other than world...is the potential for point data to be extracted or created and cause havoc. ( I know it won't ever happen to
*YOU* because you have some how managed to work around this or simply accept it as a risk. And
*YOU* knoe who you are.
)
It would be suggested that one place those NON C3D labels through the Paperspace viewport.
They will then be placed correctly to the View's UCS only you will not need to create or manage it.
This leaves modelspace always at world.
Or switch some of those dumb MTEXT notes over to General Note Labels; my guess is some of them fall into the category of Typical Notes and find their way onto your plans regularly.