Well the problem is that I was using code like this:
new Date().toJSON().slice(0, 10)
to get my date as YYYY-MM-DD string, the
YYYY-MM-DD
I haven't noticed that the toJSON method don't take into account your timezone offset
But it does, it converts the local-time to Zulu (look at the end of the string: Z)
new Date( "2012-01-02T03:04:05+02:00" ).toJSON() "2012-01-02T01:04:05.000Z"