Thank you @defalt for pointing this out! Will look into this, I agree transform function may be the reason.
Oh my... Found it.
"format": "%d %H:%m" or
is wrong. %m = Month and %s is unix epoch (Link)
Changed it to
"format": "%d %H:%M,%S" and it looks good now.
Indeed, I was testing it with %H:%M. Great, I am really happy that works for you now