That can be everyone's guess. But since the FDR and CVR data are most likely available in a few days, there is no need to speculate. I am sure the reason will come out regardless what face saving by whatever party might be involved. FDR and CVR data can be sent by email so no need for NTSB or Boeing people on site waiting for any Covid clearance.
China has grounded a lot -800 so they have some interest to figure this out.