I was just notified in my admin of the same glitch happening on my store, and instead of pointing me to which transactions were affected, Shopify is advising me to manually check all my orders from October to find which ones are not appearing on their end !
So not only did they mess up, but they’re saying I have to do their job of identifying all the affected customers. What am I paying Shopify 300$ a month for ?! Would love to know !