I assume it is a food bowl rather than a water bowl. We would recommend you don’t use a bowl and instead scatter feed their food around the cage. Scattering food around the cage encourages them to forage and is a source of mental stimulation and entertainment (vs eating from a bowl which is a mindless activity and doesn’t encourage anything). There aren’t many of us long term owners on here who don’t use food bowls.
To check, does he live with another piggy? A single piggy can get bored and you are then more likely to notice those kinds of behaviours as a way to get attention and their interaction needs met by you