Interfaces > your_VLAN > Edit > DHCP Server and check that field which I have marked on screenshot (if there is another DHCP on your network, sometimes, it helps).
Is this perhaps a MOX and not a TO since the latter has only 5 LAN ports but not 15?
Secondly, virtual interfaces are not the way for VLAN tag management of DSA ports (switch’s downstream ports).
Any/all VLAN tag management should be undertaken with the bridge v command only. Suggest you remove any all/any of those virtual interfaces on the DSA ports and reboot and then start from there (step by step) with the VLAN tag management.