MacBook Pro showing incorrect time and date

Hi All,

Since an update about a year ago my MacBook has started displaying the wrong time and date. It looks like the clock just turns itself off when the MacBook lid is shut and then when reopened just acts like its that time.

E.g Finish working on Saturday night at 7.30pm. Shut the lid and then reopen on Sunday Morning at 11.30am and the time still shows Saturday 7.30pm.

Gone into settings, turned off auto update and back on again (which fixes the issue until the next time).

Anyone have any ideas? It's really annoying!