There seems to be a huge amount of plugins that does not store their data correctly according to your explanation for the weird data at the end of some posts. But it's only on Gaven themes that I have this problem. Other themes never show this type of data at the end of posts. I love your themes, don't get me wrong, but this explanation is not acceptable.
The workaroud, to copy and paste the custom fields is a pain. I wish there was another solution to this. Apart from disactivating the plugin in of course