Items held in the offhand don't disappear when dying while any interface is open except the inventory

The Bug:

When dying whilst in a GUI, the item in the offhand stays held in the offhand in the Death screen even though KeepInventory is off.

Also, holding a totem in the offhand when inside a GUI, the totem is used but the item remains in the offhand (ghost item) even though the item was used.

Steps to Reproduce:

1. Build the setup as shown in the provided attachment. setup.png
2. Ensure that the "keepInventory" gamerule is set to "false" by running the command provided below.

   /gamerule keepInventory false

3. Input the following command into the command block.

   /kill @p

4. Hold any item in your offhand and open the trapped chest.
5. Look at the item held in your offhand on the death screen.
6. Take note of how items held in the offhand don't disappear when dying while any interface is open except the inventory.

Observed Behavior:

Items held in the offhand don't disappear.

Expected Behavior:

Items held in the offhand would disappear.