Cookie Persistence Records are not removed from persistence table after persistence idle timeout or iRule timeout expires

First off, you aren't using Cookie Persistence, you are using Universal Persistence, with a key value retrieved from a cookie.

Are you are using the iRule directly on a VS, or if you have the rule associated with a persistence profile (which itself is then associated with a VS)? If you aren't doing the latter, I would suggest dropping the timeout values from the iRule and associating the iRule with a persistence profile configured on the VS.

Universal Persistence is explained here.