I’m experiencing exactly the same issue.
I’m using Next.js and calling the Instagram Graph API to publish carousel posts. On my profile the carousel appears correctly as a single post, but my followers sometimes see each image separately in their feeds, as if I had posted them individually.

Even worse, followers can like and comment on these “phantom” posts, but I can’t find or manage those standalone posts anywhere afterward.

Have you found any solution or workaround for this behavior? Any update or confirmation from Meta would be super helpful. Thanks!