See line 1198: ObjectUtils.nullSafeEquals(this.propertyValues, that.propertyValues)
Look at AbstractBeanDefinition#getPropertyValues, line 891, which treats, in effect a propertyValues of null as equivalent to en empty MutablePropertyValues object (i.e., a side-effect of getPropertyValues is to create an empty MutablePropertyValues object when propertyValues is null).
Affects version 5.3.3