What happens if I edit inventory directly in Shopify?
If you edit inventory directly in Shopify, SKU Stock Sync may detect that inventory change and process the related SKU/location group.
If other variants share the same SKU at the same Shopify location, SKU Stock Sync may update the group so the matching variants stay aligned.
This is expected behavior when the variants are meant to share the same stock.
If you only want to change one variant without affecting related variants, make sure that variant does not share the same SKU at the same Shopify location.
Inventory changes are not always processed instantly. They may be processed during a scheduled sync, or sooner if manual sync is available and work is already waiting.