Not an unreasonable guess. I've read of issues with text converted to dates--but usually location settings were a factor.
A bit more detail than "inconsistent results" might help others to help you.
check if your date field is of type date - could be imported into or as text ..
It's not sorting by the date.
The field was a text type on import and then converted to date type.
Exported all data from the table and opened into Excel.
Set the data type on the columns that were dates to Date.
Deleted all Records in my database and imported the data back in for that table and now it sorts by date.