It is fairly traditional on Numista to list issue dates as a range, even if the coin was not actually issued over the entire range (it can get
even more hilarious than your Mexican example).
Otherwise, we'd have problems when coins were minted in many years along a range but not in many others (a particularly extreme case is
this Croatian type, which was made every other year from 1993 to 2015).
I wouldn't quite say this is entirely consistent - assuming the respective descriptions are correct, there is completely no reason not to unify
this type and
this type of Swedish iron 2 ore except maybe their separate Krause numbers. But that's another question entirely.