Gorm mongo doesn't failOnError when saving invalid nested objects

[stesteau]

@Entity
class Element implements Serializable {
	static mapWith = "mongo"
	Map<String,Video> videos = new HashMap<String,Video>()
	static embedded = ["videos"]
}

@Entity
class Video extends BaseTrack implements Serializable, Track {
	static mapWith = "mongo"
	Map<String,VideoChannel> channels = new HashMap<String,VideoChannel>() 
}

@Entity
class VideoChannel extends Channel implements Serializable {

    static mapWith = "mongo"
    
    String codec
        
    static constraints = {
        codec(nullable: false, inList: ['Uncompressed', 'H.264/MPEG-4 AVC-Intra 100'])
    }
}

element.videos['bleh'].channels['bleh].codec = "Bullocks"
element.save(flush:true, failOnError:true)

Saving Element pass without error, it doesn't validate nested objects.
If I try to save the channel I have the expected «grails.validation.ValidationException: Validation error occurred during call to save():»
Adding deepValidation doesn't work either...

Context :
Grails : 5.x
GORM : 7.3.0