Why is the Living status on Ancestry not set to match the RM status?
When you use RM to create the tree on Ancestry it bypasses Ancestry’s normal logic that would set individuals as Living if they are under 100 with no death recorded. So you end up with everyone set as deceased. (I confirmed that the Ancestry normal logic worked by exporting a GEDCOM and uploading that to Ancestry).
If the only change you make to an individual is to the Living status on either RM or Ancestry it comes up as a changed record but there is no way to make it do the change - you have to use the X.
If the tree you upload to Ancestry is going to be made public it is crucial that Living individuals are marked as such.