Mirth 3.2 - Connection / ACK issues

[mcanalld]

OS - Linux version 2.6.23.17-88.fc7 (mockbuild@xenbuilder2.fedora.redhat.com)
Java - 1.7.0_75
Mirth Connect - 3.2
Database - psql (PostgreSQL) 8.3.11

Channel Source is setup as:
TCP Listener
All interfaces
Port: 6677 (tried other ports same issue)
Source Queue - On
Response - Auto-generate
Transmission - MMLP
Frame - <VT>{message}<FS><CR>
Mode - Server

Recently upgraded one of our servers from 2.1.1 to 3.2.Been having some very odd issues with TCP Listeners / MMLP. When I deploy channels I'm able to telnet to the ip/port (on a different PC). However Mirth does not show any connections and running - "lsof -n | grep {port}" shows as Listening, but nothing connected. Rebooting the entire server sometimes gets the channels working however once I do a redeploy it instantly breaks. I ended up having to revert back to Mirth 2.1.1 using java 1.6 and works fine.

I also ran - "tcpdump -nn port {port}" then connected via telnet and it shows the connection happening. Again, Mirth shows no connection nor does running "lsof".

When actually trying to send an hl7 message to that channel, from another mirth server, the sending mirth gets timeout waiting for ack, nothing ever received.

I'm so confused what could be happening......