Quantity is 1 but availability is 0. Bug?

What does “missing offer” mean?

I use inventory loader spreadsheet and set quantity to “1” for FBM. I upload then and listings say “missing offer” and shows “0” for availability. However, when I click “missing offer” to edit the listing it shows “1” for quantity.

Why is availability 0 yet the quantity is 1? This makes no sense.