This is an intermittent problem. We have a custom form login page that works fine when using any browser and all the images are displayed. We also use the "sys_APM_MS_Office_OFBA_Support" irule that allows our outlook client get prompted for the same login page when accessing some calendar resources in sharepoint. This works great by the way accept the images of form login do not always display and mostly do not. We do see some 302 error in fiddler when it is not working
Some more information: We are able to get the form images to appear every time (but not a solution).
So it is using a shared cookie or the cache images or something. I am trying to go through irule to see if it is not setting a cookie that gives permission or something to the images???
So that is why in fiddler we do not see the paths to images when it is working. Do you know what change we could do to get it to work without going to Internet Explorer first?