Plea to Data Doctors: While many of these problematic dates are due to fairly simple issues like typos or incorrect handling of a "double date" from the years before the Gregorian calendar was adopted, please be aware that many of these problematic dates are very tricky. Please don't delete a date to make an error go away (yes, unfortunately, I've seen data doctors do that :-( ) and please don't change a date to make an error go away unless there is a solid basis (ideally a source) to support the new date.
Some errors are due to errors in the original records. There are people whose wills were recorded for probate a full year before they made their will. And children whose births were recorded three months apart. Etc. Please don't make arbitrary assumptions about what really happened in these cases; we descendants may be stuck reporting what the records say and noting the discrepancies. Others of these problem dates may result from errors in the genealogical research, such as connecting a child to the wrong father. Resolving those typically requires careful research.