1. Whatever magic let me play normally for the past X years without UPnP, disappeared on update 33.0.1 (April 27th). Preventing me from hosting games and the other expected symptoms. Gameplay was not affected by 33.0.0, only 33.0.1 up to 33.0.3
2. Upon setting up port forwarding and confirming that hosting worked once more, StrictNat message continues to display on log in.
Extra Details:
PC, Steam.
Network Administrator confirmed no changes to network settings.