You could be running into this issue:
Issue 133436 is reported as fixed in 6.5.4.0.
Issue 147369 is reported as fixed in 6.5.4.0, internally as well
If you have a Window, I would (1) backup flash (2) copy it off (3) Upgrade to the latest 6.5.x.x to see if it fixes it. You can also open a TAC case to get more specific advice.