Gutenberg custom block validation error due to meta attribute not populated

I’m creating some custom blocks for Gutenberg.

The current one I’m working on has some custom attributes stored in meta – the specific one I’m working on right now is called ‘createdDate’.

attributes: {
        createdDate: {
            type: 'string',
            source: 'meta',
            meta: 'page_created_date'
        }
    }

in registerBlockType

I can see that when I save, the value is persisted to the DB.
The value is also displayed in the front end.

However, when I next visit that page in the admin section I get a block validation error. It seems to be that attributes.createdDate is null until *after* the block validation test at which point it’s populated, meaning the HTML block differs to what’s stored in the DB.

Is this expected? Is there a way around it?