The template processing code caches the compiled byte-code for each template file it encounters.
One problem with .LRN's "new-portal" packages - used heavily in .LRN - is that it dynamically generates a template string, which is then parsed. The result of this is not cached ... the portlet code it includes should be cached, but the execution of the wrapper and I believe the master (which in .LRN is a bit complex) won't be.
Just more detail to consider.
