On March 4, 2020 the CDC changed how to fill in a death certificate for COVID-19. Typically a death certificate is filled in with the underlying cause of death on the bottom line in part 1, and this is what is reported to the Federal Registry of Disease.
This is not the case for COVID-19!
“COVID-19 should be reported on the death certificate for all decedents where the disease caused or is ASSUMED to have caused or contributed to death.” [emphasis added].
Any markings of uncertaintly on the death certificates with words like suspected-, probably-, maybe- COVID-19, the US system would automatically default to COVID-19 as designated by ICD-10 codes.