I have several apples to feed my pet that are not showing up in my pet's inventory. I've included images comparing both my character inventory and my pet's. Notice how few apples appear for the pet when both inventories should be displaying the full amount of apples.
After some testing, I discovered this issue only impacts items held in the second +10 Item Capacity (PayVault item) segment of my character's inventory. Items held here are invisible to all pet inventories.