One of our users received this error when trying to save a new page: "Failure to convert edit format to storage format" and then lost the data because he noticed the error saving draft issue which prompted him to attempt a save.
I did a search on this and only find responses from some Atlassian's that they cannot reproduce and have closed out the bugs. But, there continue to be comments from customers and Atlassian users that are providing feedback on how to recreate and are still having issues, but no response as to how to address.
See these two issues for reference - both closed:
https://jira.atlassian.com/browse/CONF-25944
https://jira.atlassian.com/browse/CONF-25714
https://jira.atlassian.com/browse/CONF-24050
Does anyone know how we might resolve or problem instructions on what not to do to avoid this issue?