Which distro you're on?
Perhaps 'date' command is showing time in different time zone, and 'clock' is showing something else. However, if it's not the case, then run commands with option to check seconds as well, then you can compare both times, as:
~$ date +%H%M%S
~$ clock +%H%M%S (Not sure about syntax, so check it first through manual of clock cmd)