Umbilical Hernia and Diastasis Recti

No. Diastasis recti is a very specific term which describes spatial separation of the rectus muscles without a hernia in between. The fascia (or strength layer) of the muscle is still intact. It is not a hernia. It is not related to hernia development. There is no medical risk to have a diastasis.
That said, some patients have a hernia repaired and the repair is bridged, not closed. The result can be a diastasis (or separation).