Cannot stack arrows in off-hand when rest of inventory is full

I can't auto pick up arrows when I am holding arrows in my off hand, however I can if I have an empty inventory slot, and then they will go into my off hand with the others. 

Steps to Reproduce:  

1. Put an arrow in your offhand, and drop an arrow on the ground  
2. Fill every other inventory slot with items besides arrows
3. If in creative, switch to survival
4. Attempt to pick up the arrow

Observed Results:
You are unable to pick up the arrow until a slot in your inventory is free. Once you have a free slot in your inventory the arrow is picked up, and goes to your offhand.

Expected Results:
The arrow is picked up, and goes to your offhand.