.getDate() returns incorrect date for year 1947

Hi,

I am using Servoy 3.5.10 and I am encountering this weird issue with the getDate() method. If i retrieve a DATETIME field that is the equivalent of 19-05-1947 in the variable vBirthDate, and i do this:
var vDate = vBirthDate.getDate()
i get that vDate is 18! When it should be 19.
This only happens if the year is 1947.
Any ideas on this?
Thank you,
Diana