I’m not a Bus pilot, but just pulled up the A321 FCOM on my EFB put of curiosity. The section on setting the clock in internal mode states it must be completed within a minute of the CFDS (Centralised Fault Detection System) will need to be reset...[which] is a maintenance operation. Not seeing any warmings not to meddle with clock apart from that (yes I know that normally you wouldn’t but if it’s wrong, you might.)
On another note, just reading the clock section made me glad I’m on a Boeing. I need a lie down in a dark room after that!