Using the GL-inet firmware with hopes that their support would be able to help fix the problem. I must compliment them on how responsive they are, but have been unable to resolve the issue.
Work-around I found is to configure the Mango to use one of the cloud DNS services. I am guessing that option somehow bypasses the VPN for DNS traffic. I only tested it once, so don't know for sure if this will make the device usable for my needs.
I typically only use the Mango while traveling, so I won't know till next time I travel.