In the last few days I’ve had two collections that suddenly started returning an “instance not found” error when trying to query documents via the GraphQL API. I also get the same error when trying to view the collection from the web dashboard collections view:
It seems to me that the collections have somehow got corrupted. There had been no writes to the collections prior to them becoming corrupted and no TTL is set. The only way to fix the issue was to delete the collections and reinsert the data. Luckily the two collections that were affected were collections where I can easily create the data. If it had been the Orders or Users collection I would have been screwed. 
This is quite concerning so any help would be greatly appreciated! Thanks in advance!