Just had a go at refreshing the epg data again. Its grabbing all the right info just cant update the info on disk i wonder if its setting the data to read only or something after the first grab?. Anyway lets see what happends when your next release becomes available.
This is a problem with Media Portal not the Plugin.
Change the update frequency in the settings for EPG, it is normally set to 24 hours. Look at your EPG.log and it will show lots of Last Updated blah blah update not needed.