Researching mortality during the COVID-19 pandemic has been challenging due to methodological inconsistencies and the limited availability of vital statistics data. At the beginning of the pandemic, the World Health Organization recommended daily data publication to inform policy response, but these data were often poor. Final data on COVID-19 deaths in many countries are not yet available, especially for 2021. This report shows that many countries have significant inconsistencies between the preliminary number of deaths and what vital statistics and excess mortality indicate. The inconsistencies in the mortality data raise concerns about the reliability of analyses and public health recommendations.