Items on my main are slotted in invalid locations. Clicking beer let's me use it but clicking Milk Tea states "You are trying to expand the slot more than the maximum capacity."  Pressing X for the description works. Trying to put the items into storage states "The slot number is invalid."

Sounds to me like you had a value pack, the items were in the free slots the value pack gave you, and it ran out with those items there and now you cant use them. Is that the case?

Ah, that sounds familiar. Just started playing 2 days ago. Any suggestions?