Closest I can think of is that if you delete your account, public posts may remain on other instances. This is one of the hard parts for federation and decentralisation to handle. The alternative would be to verify every action that occurs on every server across the entire federation, but then we’re looking at exploding performance costs comparable to crypto.

I don’t off-hand know if it stays this way forever, or if it eventually fixes itself.

But Lemmy’s codebase as-is doesn’t track anything you haven’t purposely submitted to it, namely your authentication details, subscribed-to communities, and posts, and these are deleted on a best-efforts basis upon account deletion.