Possibly due to the fact the posix timezones tend to use ISO 3166 as a basic formation of standard, the "EST" abbreviation is somehow mistaken as "Estonia". Just a guess, mind ya. Also not the sort of boggle that keeps me awake nights, but if ya really must know ya can always Google for "posix timezone" and surf a few results.
ObGeek: It's not "incorrect results", it's "unpredictable results".
/yes, there is such a place as Estonia
//despite of what you may've heard from Pauly Shore.