This issue can occur when you create new products by duplicating existing ones. When you duplicate an existing product to create a new product, Shopify also automatically duplicates the translation data of the existing product to the newly created one.
When our Translate My Store & Currency app detects the new product, it sees a brand new product that already has translation. In such case, this new product will be seen as translated even though the translation data is actually for the other product.
You can avoid this issue by following these steps when you create new products by duplicating old ones:
1. Duplicate the product with Shopify admin
2. Go to the App and scan the store, before editing the new products at Shopify
3. Once the scan is done, go back to Shopify and edit the new products
4. Once that is done, go back to the App and scan again
This way our app will see the base text has changed, but the translations have not, hence the App flags their text as "not translated or outdated" and you can easily find them and correct translations in the app. We have contacted Shopify about this, to suggest they they do not automatically duplicate translation data in this way.