Thanks for the help!
You are not alone.
We are having the same issues. We use a custom API to sycn inventory between Cova POS and Shopify.
This issue is recent for us. I noticed it after the documented dashboard issue with Shopify yesterday.
It is affecting new items on new collections and old items on collections where I changed the tag for the entire collection.
It appears to be only new tags that were created yesterday for us, but it may have started on Monday Sept 13 as well. We did not tag the Sept 13 items until Sept 14.
We chatted with Shopify support and it was logged.
We have checked Metafields Guru and it does not seem to be that app and Flow.
Any updates on your end?
We have just recently went through this issue as well. One of our tags was randomly removed from products, removing them from our site. We are trying to frantically track down which products are missing and have no clear path on the issue. Any information on this would be greatly appreciated.
We went back and forth with the API developer and our POS support. We were told weeks after it started that this had something to do with a Microsoft Azure update. I am not sure if this applies to you if your issue occurred recently.