From the problem description provided I believe you have a browser caching issue.  I am sorry to hear that you are experiencing this issue. Please do the following:

•             Log out of all Pega sessions

•             Close all browser tabs

•             Clear complete browser cache

•             Restart browser and retry

•             If issue persist try incognito mode

•             If issue persist try a different browser

Please let me know if this resolves your issue,

Sean

Pega Academy Self-Study Support Team