The item does load instantly in the left hand, that happens whenever the player does:

-Placing or replacing an item in the left hand.

-Updating the amount of the item on the left hand.

-holding a map in the right hand while holding an other in the left hand.

-Using a bow while holding an item on the left hand.

What was expected:

Rendering the off-hand item loading animation probably just like with the right hand when doing these thing I've listed above.

What actually happend:

The item just vanishes instantly without animation whenever I do the listed things in the above.