Using the custom loot window, when I loot items, it always says +1, regardless of actual amount looted. Money seems to display fine, just items are off.

Hi! It will be fixed in the next update.
It's an interesting bug. I find the actual number of successfully looted items by matching the x2 from the end of the message. But in Classic, the sentence ends with a period . (in Retail, it ends with a number).