With sync, do the reports automatically get updated after an issue got fixed?

It updates as soon as you visit the fixed page. No need for a cache clear.

It is using the URL as the unique key though, so you can sometimes end up with a record that needs to be manually dropped if you change an alias. Usually clicking through from the dashboard takes care of that (the "ed1ref" query variable is to check for that). I'm working on switching to using NID/TID as a key when available.

If this is happening every time you may have found a bug.

Closing for now; please re-open if something is not working as expected.