The Geni Consistency Checker will report "Two digit year" on any profile with a life event (birth, death, marriage, etc.) with a two-digit year. This is often a mistake of omitting the century, for example "born in 46" when the correct year should have been 1946.
Why not 1-digit years? Single-digit years are less-commonly mistakes, and Geni does have profiles that go back as far as the first century, so single-digit years are ignored. Master Profiles are also exempt from this check, as they have been vetted by a curator and many first-century profiles are expected to be Master Profiles.
This inconsistency is always considered a Warning
Auto-fix: There is no auto-fix for this inconsistency, but most fixes will entail editing the event to add the correct century. If indeed this is a first-century profile, you should mark this inconsistency correct by clicking the "Ignore" link at the bottom-right corner of the inconsistency and then choosing "Mark this correct for all users."