Weird default value behaviour

[VojtaStanek]

I have following schema:

export class Article {
	// [...]
	publishedAt = def.dateTimeColumn()
	// [...]
}

Admin definition:

<DateField
	field="publishedAt"
	label="Published at"
	dateFormat="d. M. yyyy"
	defaultValue={new Date().toISOString()}
/>

Current behaviour

When editing entity which has publishedAt set to null administration shows the field filled with specified default value and save button is disabled. When the field is cleared, the save button is enabled and persists the default value.

Expected behaviour

a) After clearing the field, it shouldn't persist anything and the button should be disabled.
b) Before clearing the field, the button shouldn't be disabled.

Admin version: 0.6.52