There is no redirect coming from the app server. I wrote a simple jsp in the deployed app that just shows the contents of the request.getRequestURL() method, and http://my.domain.com:80/myapp is what I'm getting from F5.
I am new to the device, and it is actually being managed by another office in my company, so my access is limited. They've setup the SSL VIP (with a valid cert), pool, and had to do a snat to route responses back to my office correctly, but there are no other iRules in place for this VIP.
The F5 technician assigned to the case did not know why our application was getting port 80 in the request either, and offered no help on ways to debug. This forum looks like my only hope for descent support.