PD4ML does not “officially” support HTTPS, however it implements very basic HTTPS resource loader (using the standard JDK classes). WebSphere and Weblogic implement their own versions of HTTPS protocol, and the implementations are not derived from the standard API. That causes ClassCastExceptions (or some strange behavior) on the platforms by attempts to load HTTPS resources.
As you wrote, your application runs on Tomcat platform, we never experienced such problem with. So first I would recommend to upgrade to the most recent v371b1 and to check if the problem is still there.