Shopify does not hold a single number for a variant's stock. It holds several, per location, and returns touch a specific one. Most confusion about counts after a return comes from looking at the wrong quantity.
The quantities
On hand is everything physically at the location, sellable or not.
Committed is stock reserved by orders that are placed but not yet fulfilled.
Available is what the storefront can sell: on hand minus committed, minus anything set aside as unavailable.
Unavailable covers units that are on hand but not for sale: damaged, reserved for quality control, or incoming.
Incoming is stock on a purchase order or transfer that has not arrived.
What a sale does
When an order is placed, committed rises and available falls. When it is fulfilled, on hand and committed both fall. The unit has left.
What a restock does
A restocked return raises on hand and available at the receiving location. That is the adjustment an audit looks for: a positive change in available quantity for the variant, at a location, shortly after the return completed.
If the disposition was damaged, the right outcome is either no change (the unit is gone) or a rise in unavailable rather than available, depending on how the store handles seconds. Either way, available should not rise.
Where returns go wrong in this model
- A refund with Restock unticked changes nothing. Available stays down. The unit, if it came back, is invisible.
- A restock at the wrong location raises available somewhere the unit is not. One location shows phantom stock; the other shows none.
- A restock on a variant that has since been changed may land on the wrong variant, or fail quietly.
Checking it
For any return, find the variant and location, then look at the available quantity's history. The adjustment should be there, with the right sign and size, close to the completion time. When it is not, the count is wrong and the return is the reason.
StockReclaim watches available quantity per variant per location and matches adjustments against restock claims. Read about multi-location and Rule D.