Fails to forward message if one of the recipient's mailbox is full

[bunyevacz]

I have an email address, which autoforwards each email to 3 different persons.
One of the mailboxes is full, and blocked sending mails to the other two persons.
From the three mailboxes, one is external (@gmail), the other two are internal (within wildduck).

Once I raised the quota of the mailbox, after a little while I got the original email to the external address.

[naturalethic]

I hadn't received any mail for two days. Found this issue and checked the quota, sure enough, quota was maxed. The problem is now that no mail was bounced, and there was never a warning. So any mail I received was essentially black holed as far as I can tell.