side effects when calling notify change on a null value

run the attached example

1. type a value into "special account"
-> not yet saved to the VM because of conditional save
2. type a valud into "account"
-> not yet saved to the VM because of conditional save
3. click the "notify account" button
-> this will only notify change the account pproperty, but the specialAccount will also load, and the typed value (into special account) is lost

suspected that both values reload because both resolve to null
this does not happen in ZK CE