Cannot delete existing custom field values after Types update

Symptoms

The Types 3.4.6 update introduced a problem whereby existing custom field values cannot be deleted when editing posts.

This affects both the Block editor and the Classic editor.

Edit a post where a custom field, e.g. a single line field, has a value and remove its content, then save the post. The custom field should be deleted, but it is not.

Workaround

This has been fixed with Types 3.4.7