This isn't a WP version specific issue.
LOVE that enkoder convert all e-mail addresses... until it hit the e-mail address in a paypal button. On the page to the right of the button image now shows:
I replaced the real e-mail address with firstname.lastname@example.org in the above example.
Since the paypal button code has an e-mail address in it, Enkoder converts that too and breaks the paypal button's functionality completely. Since the site only sells one item it wasn't worth the effort to set up a full e-commerce system.
Just wanted to comment about this particular conflict.