Local network cease to work when VoIP interface is enabled

[chocointed]

Still a learning user for OPNSense here so bare with me

Currently I have a VM running OPNSense that's running on my server to control my home network.

And with that I have a BCM57810S SFP+ card passed through running an ONU SFP stick with a 10GBase-T transceiver to serve as an uplink to my 10GBe switch.

Currently the ONU SFP stick is running in transparent mode to passthrough all the VLANs from my provider as upstream to OPNSense and in OPNSense. I have three VLANs setup at the moment. VLAN400 (VoIP), VLAN500 (PPPoE Dialup) and VLAN600 (IPTV).

VLAN500 is quite straight forward with pppoe/bridge-to-bridge interface, nothing's wrong there. However, when I enable my VoIP VLAN and the bridge that bridges VLAN400 with igb2 (Dedicated interface to run VoIP) in DHCP mode, I lose all local internet connectivity. Same with my IPTV VLAN.

My VoIP DHCP address assigned from my ISP side is 10.x.x.x, basically RFC1918. I tried turning on this interface does not require an intermediate system to act as a gateway for both VLAN and Bridge interfaces and still nothing, I enable the interface, enable DHCP and I lose all connection, I can't even do a speedtest-cli in ssh.

Is there any settings that I can turn on/off to make sure that turning on VoIP interface does not screw my local network?

P/S: As far as I can tell, it only affects local network connectivity, even when the local network doesn't function, I was still able to access my port forwarded NAS from a remote connection.

Would appreciate any advice given from the novices veteran OPNSense user here 
If screenshots are needed, I will be more than happy to be able to provide any screenshots needed to help with diagnostics