Hopefully everyone can follow this... Not too good of a writer.
I have experienced Shopify POS inventory problems for quite a while but things usually tend to even out after a couple minutes to about an hour.
Example: Create new product - enter all information, prices, barcodes for variants - mark as active across all channels. Sometimes Shopify POS will take a handful of minutes to an hour to sync with the admin page information. Barcodes still work... So item will ring up as out of stock, but that -1 in the POS will become 0 in the admin page. Eventually the stock numbers will appear in POS. I am okay with this. This works out.
The problem is... Occasionally it decides to not sync! Sometimes a product will have full info, inventory, prices, barcodes, active on all channels, etc. but the inventory on Shopify POS will say SOLD OUT for every variant AND the barcodes will not work even though they are correct in the admin page. The product still appears in the POS but you have to search the specific name and add sold out item to the cart. The -1 in the POS will then sync with the admin page making the product 0 and THEN the barcode works for only that variant.
If anyone has had this issue, you can fix it by deactivating all of the channels, save, change active to draft, save, re-enable channels, save, change draft to active, save. Just to be safe... Probably only have deactivate Shopify POS, save, re-enable.
BUT... I only know this is happening when I go to scan a barcode for a product. I have all of my shoe sizes as tiles on my POS, so if someone asks for a size, we can pull up all of that size and examine the availability on the shoe wall. But if the items are marked as Sold Out, nobody knows if they are physically in the back room and are looked over. Shouldn't have to add product to the admin page then double check EVERY BARCODE to make sure it appears in the POS.
The IOS POS app is always updated and this has only happened a handful of times.