Howdy ewordlinx,
I created a test event for the third Saturday on my site and was able to edit the recurrence description sucedsffuly (as seen here). I do not believe this is a bug with the default environment.
What happens when you try and edit the description? Does it just not show up after you click save? Are oyu able to edit other events recurrence descriptions? Would you mind if I logged in and tried to edit it myself? Obviously you would need to create an account with the appropriate permissions for that. If you do want me to personally test it, please post the login credentials using the “Private reply” checkbox.
Please let me know the answers to those questions. Thanks!
– Brook