This seems to happen very rarely but i have had it occur twice where a luggage will simply vanish and never be heard from again this seems to happen on smp servers when they crash but only when the luggage is in entity mode.

I have a suggestion to fix this that would also serve as an anti theft device

essentially crafting the luggage will generate a skeleton key with a unique identifier. this key will be the item that actually stores the luggage's inventory and the luggage entity will simply link to it.

right clicking with key in hand will summon or spawn the luggage if it has been deleted
shift right clicking the luggage will despawn it but not drop an item.

this allows for more stable inventory that can persist through a server crash even if the entity has been deleted. additionally requiring the key to spawn the luggage and not dropping an item when the luggage is despawned prevents another player from stealing a luggage while you are offline and means that the luggage can only change ownership if you physically give someone the key. I would say that this is letting a potential thief off easily since in the diskworld books the luggage has been known to eat people who tried that XD

I don't like this idea. We just needed to fix luggage despawning. Closing this issue, but thanks for the suggestion.

"I lost my key..." What now?

the luggage could give a copy of the key to it's current owner when shift right clicked

This sounds like a dupe bug waiting to happen if the luggages are unloaded, and keeping track of the keys location as it changes through pipes seems like it would be a nightmare.