Hi
Have you recently downloaded any apps ? If so it could be a rogue App.
If not and it continues then I'd create a Back up and factory reset.
If that does not resolve the issue then if the phone was supplied by Vodafone directly they apply a 24 month warranty. Take it into a Vodafone store. They'll check it out and if necessary send it off to their repair centres.
Current Phone >
Samsung Galaxy s²³ Ultra 512gb Phantom Black.
