Not sure if the upgrade is related to the issue or just a coincidence, but after I upgraded to premium yesterday I have not been able to post any new trades. When I click one of my keys in my shop inventory and press on the '+Trade' button, it just loads the home page for a second time (a second copy of my home page get inserted at the top of the document). The 'new trade' interface never appears. I've tried both firefox and chrome.
I also ran into a second bug today: I tried to withdraw some keys earlier and the bot sent me the same trade offer 3 or 4 times. I imagine that bug is more common tho since steam responses aren't always reliable. Thought I'd just mention it anyway.
Thanks for your time.