Found the bug. It will tell you the port range is already open when you have opened a port range higher than the one you intended.
eg. I want forward port 80 but have previously port forwarded 8080 to the same ip address.
You have to delete the rules and then enter the port forward in ascending order.
eg. Ports 22,80,443,8080 in that order.
Hope it helps anyone else who is suffering the issue and hopefully the VM team can fix it properly.