It seems that when you use "Re-read Codecs" from the Tools menu the episodes are ignored. Thus in the Media tab page of the episode is nothing filled in with the codec information of the linked file.
In the plug-ins category of this forum I have added a few programs to test. One of them is a prog that reads more info from the codecs - but only for movies. I haven't add that ability yet as for episodes only the first audio is stored. Therefor another prog is able to autocorrect the path of episodes what XMM also does not handle. http://www.binaryworks.it/forum/topic.asp?TOPIC_ID=15422
In order to achieve what is possible, you have to try the impossible over and over again. Hermann Hesse