Are you sure it's mould and not staining? If it is mould is the pot being stored with the lid on?Now then, need a bit of collective wisdom.
Muggins here has a slow cooker that we use fairly regularly. Getd put away after it gets scrubbed clean and all that mullarkey. Twice of late it developed a blue mould inside the ceramic pot after storage. Twice scrubbed to buggery as a result. Today, after being stored in clean dry surroundings....blue mould.
Any idea why this is and would a bleach wash help ?