Twice now we have run into problems in JIRA where data shown in an issue list differs from the detail page of an issue. The first time, the state of an issue was wrong on the issue list. The second time, the summary was wrong. The first time, I cleared the issue cache -- even though the cache was supposedly disabled. This appeared to clear the problem, but someone else had also added a comment to the issue so I don't which action (if either) caused the update. The second time, I restarted JIRA to no effect. The problem went away after I changed the summary of the issue, although someone else had tried that a couple of times already.
The next time this occurs, I am going to try re-indexing using Administration/System/Indexing.