I have multiple Mastodon instances and a single ES node.
When I ran chewy:deploy on one instance, it created an index named statuses_1550441830498. I don’t know how the name is chosen (maybe it’s stored in the chewy_specifications index?), but when I ran chewy:deploy on a second instance, it added documents to the same index.
Yes, I think that’s a problem. Sharing ES between multiple instances hasn’t come up before, I think we are missing a namespacing option. I do not know offhand how to configure a namespace for Chewy. But I recommend temporarily either deleting the index or disabling ES in all but the one instances.