Player drops 2 items from the hotbar at once when the Survival Inventory tab is not selected

Steps to reproduce:

1. Obtain 2 (or more) of any item and put them into one of your hotbar slots
2. Switch to tab other than Survival Inventory
3. Use the Drop key on the stack once

Observed result:
You drop 2 items at once.

Expected result:
You drop only 1 item, like previously.