Test Cycle disappearing
I have recently had a Test cycle disappear from the cycle summary for a release, even though when I looked at Test Executions I can see that Test cases are still showing as added to this Test cycle. ...
Forum Discussion
I've had this happen, I figured out if there are too many folders under a release it starts "losing" them just as you described. I ended up creating some "releases" for each year and archiving test cycles into them to take them out of the active rotation.