If I go to dispenser.tf, the page loads fine. But if I to go 'My Shop' the page loads very, very slow for me. I am sure this is because, since I expanded the backpack of my bot, I have close to 800 items in the inventory.
Also, when I try to add another trade, the process goes a long fine(though very slowly) until the final 'create trade' button. Then the button just greys out and the page hangs. I have left it like that for hours trying to add a one item trade, and it didn't work.

Do you want to buy "Any hats" or "Any weapon" in the trade? I got the same problem...

Same here. It does seem like I can create any trade I want, EXCEPT it if it has any craft hats or any weapon on the right side

If you're still can't add new trades, then try logging out of Dispenser.tf (logout button in top right corner) and logging back in again

For me, this seemed to be enough to force a reload of the updated files, which fixed the problem