FormsLauncher class not found after upgrade to 12.1.3

Hi,We are running across random occurrences of not being able to launch forms after logging in. We are in the process of upgrading to 12.1.3 and this is the second iteration of our upgrade. After we finished the upgrade we noticed that users were running into the class not found exception randomly. It would work for some users but would not for other users. We have looked at all the notes referenced here but it didn't help. We have tried emptying out the java cache, the browser cache and rebooting. Sometimes we are able to launch forms successfully after clearing out the caches, but the problem re-appears again. We have also checked proxy settings on the browser.