If you're over capacity, it should always create a storage block meta-item that holds the items.

When you log out, over-capacity, with no meta items inside your main inventory. It will not create that item when you log back in. Your items will be gone but there will be no storage block meta-item.

This will not create an item on respawn:

This will:

How to reproduce:

1. empty your inventory
2. put a few stacks in your inventory
3. relog
4. all items will be gone, no meta-item created

1. empty your inventory
2. put a few stacks in your inventory and include 1 or more meta-items in your MAIN inventory, not in your hotbar
3. relog
4. all items will be gone, meta-item is created