zimbra still using /opt/zimbra/backups even when disabled

we have a serious problem with our partitions / volumes.

we have several separated volumes and zimbra insist in using first one /opt/zimbra/backups when you perform an export operation even with that volume disabled. /opt isn't intended to be used as store, just as system and everytime we perform an export to another partition we can see BOTH partitions growing up.

I'm not sure if by design zimbra/zextras is still using /opt/zimbra/backups as temporary storage, but we need a solution for this as our system partition is filling up to a dangerous level.