Thanks to those of you that offered a suggestion. I built a second RDS server and applied my group policy and browsing was fine. I then started to think about what I needed to do to move it in to production and replace the one that had the browsing issue. Then it hit me.... I have load balancing on my SonicWall. RDS is mapped through the firewall on https. Therefore requests that went out over https could go out over either interface, but always came back on one. This is why it would sometimes work. This is also why most other sites would work, but https (in this case Office 365 which always goes over https) would only work once in a while. Adding a route to force all traffic from the RDS server out over the interface that traffic will come in on fixed the problem.