The Geni Consistency Checker will report "Unrecognized suffix" on any profile that has text in the suffix field that the system does not recognize as a valid suffix. The list of suffixes is quite long but constantly being adjusted -- if you feel the suffix should be considered correct, you can mark it as such by clicking the "Ignore" link at the bottom-right corner of the inconsistency and then choosing "Mark this correct for all users."
This inconsistency is always considered Informational
Auto-fix: There is no auto-fix for this inconsistency. The suffix might be misspelled or incorrect, or perhaps it should be marked correct for all users.