Please turn off inventory sync between Blast Ramp and Shopify
Go to Advanced > Administration > Integration > Shopify configuration > Edit
Uncheck Enable Inventory Sync and Use Full Inventory Sync
Things to be aware of:
Orders from Shopify are imported into Blast Ramp every 30mins.
Inventory sync takes place every 60 mins.
When there are many orders coming in, there will be a lag between the order and inventory sync causing the two systems to be out of sync.
ie. there are 50 items ordered not imported into Blast Ramp yet. In Blast Ramp, there are 100 units in stock, but in reality only 50 left. When the inventory sync is scheduled, Blast Ramp will overwrite Shopify's inventory, as it is supposed to. Now Shopify is back to 100 units instead of 50 units.