User Configuration > Administrative Templates > Microsoft Word 2016 > File Tab > Check Accessibility
User
HKCU\software\policies\microsoft\office\16.0\word\accchecker
This policy setting prevents the Accessibility Checker from verifying that tables do not have merged or split cells. If you enable this policy setting, the Accessibility Checker will be prevented from verifying that tables do not have merged or split cells. If you disable or do not configure this policy setting, tables will be checked for merged and split cells and any issues will appear in the Accessibility Checker.