When you go into AMPCLI -> Enter Commands, what is the output of the date cmd?
11 Enter Commands
q >> Quit
Your choice: 11
Running Enter Commands
Type 'help' for the list of commands.
$ date
Wed Jun 27 07:33:54 PDT 2018
Is that matching what shows on the System -> Performance page? If not, then there's probably something wrong with the TZsetup, you can try re-running the timezone setup from the AMPCLI -> Advanced -> Timezone option. If the issue still persists, then you can open a support case and support can try to debug if something else is mudged in the background.