I am on JIRA 6.3.x
I have set up a project with its own Issue Type schema. After a month or so, they came to me and told me that many of their issue types had gone missing. I checked their project and its associated issue type schema - and it was still OK. However, I was able to replicate their problem - when i went to "Create" an issue in their project, the Issue Types list was quite small (and included one that doesn't exist on our server!)
I can't fathom why this is happening. Any ideas?
(These folks do have project admin, but I am not sure what they could have done to cause this).