If you have setup Shopify items, but not via the Merac Back Office, and these items keep getting set to Draft. This will be because your integration has Allow deactivating of inactive products ticked.
This means that any item in Shopify that is not ticked as a Shopify Item in the PLU Maintenance within the Merac Back Office (see screenshot below) or the item is not derived from Merac will be set to Draft.
If you would like Allow deactivating of inactive products setting changed, please contact support via the portal to get this changed for you.
However, this will mean you will need to manually set PLU's that were previously set as a Shopify Item in the MStore Back Office but now this has been unticked, to Draft.