Khaled: It's a simple DST bug with $gmt that should be possible to correct.
Desired output, all the time any time:
$gmt(0) == Thu Jan 01 00:00:00 1970
During the summer months, during local DST, these outputs are violated and unreasonably change.
$gmt(0) == Wed Dec 31 23:00:00 1969 (wrong)
$gmt() should be local-time-DST agnostic. Epoch happened Jan 1 1970 at midnight.