I had my companion with a full backpack of gear she was holding on to for me, and when I travelled back to my realm I found her held items was entirely missing. She is set on Do Not Add Fuel and I looked around all my trunks and didn't see her having deposited anything. Her worn gear and weapons are still in place, just the inventory I had her holding was gone.
Ok to close - the companion dumped everything into a random chest which was still flagged Survivor.
My husband had a similar problem when he travelled back from a Desert Herbarium to HIS Abeyance realm.