I reported a similar problem a week ago but did not receive a reply.
Drafts were disappearing after editing them. And some would accept the edits, but the next time signed in, they would be gone.
I hope support fixes this soon.
Sorry for the inconvenience, but this issue was caused by a flakey database server in one of our datacenters. Once the problem was identified, the server was removed from production and fixed. This problem only affected a small % of WordPress.com blogs and only some of the time since we have multiple datacenters which store and serve your blogs’ contents.