I specifically reproduce the issue in wandering trader's trading screen. And I'm no idea if it would happen in other trading screens. Apparently I used add-ons.

Steps to reproduce

1. Find a trading term that requires two types of items
2. Hang your cursor on the second item slot and note shown name of the item
3. Open another trading screen that has same quatity of trading terms. Especially a trading screen contains a trading term requiring one type of items at the same position of the trading term metioned in step 1
4. Hang your cursor at the position of second item slot

Expected situation

No text hanging

Observed situation

The text you noted is hanging. But when you are choosing the trading term, the hanging text disappeared.