Happened to me already. Created a new branch but it kept me informing me the non-existence, retried a few times and shortly after was created with a bunch of duplicates.
Same here, but last night I was trying to post a comment to another repo, refreshed and tried again like 5 times before realizing there was an outage and it wasn't on my end. This morning that issue has 5 dupe comments (so I look like an idiot), and deleting them does nothing; they just reappear when I refresh the issue.