some additional comments to clarify the partially bogus course_id.

cms/djangoapps/contentstore/views/preview.py

@@ -155,10 +155,12 @@ def load_preview_module(request, preview_id, descriptor):
             "xmodule_display.html",
         )
 
+    # we pass a partially bogus course_id as we don't have the RUN information passed yet
+    # through the CMS. Also the contentstore is also not RUN-aware at this point in time.
     module.get_html = replace_static_urls(
         module.get_html,
         getattr(module, 'data_dir', module.location.course),
-        course_id=module.location.org+'/'+module.location.course+'/REPLACE_WITH_RUN'
+        course_id=module.location.org+'/'+module.location.course+'/BOGUS_RUN_REPLACE_WHEN_AVAILABLE'
     )
 
     module.get_html = save_module(