Diamond Shaped Question Marks Littered Posts of Sites Of Users When Upgrade To MultiDB 3.0.3

Multidb 3.0.3 has a problem as it convert most users blog on my wordpress/buddpress multi site with characters with diamond shaped question marks in blog posts. When I checked, I see that users' blog posts' html source and even inside their dashboard does show utf-8 character encode. To solve the problem I have a test user to export the old posts, and delete site, recreate site and reimport posts to strip away diamond shaped question marks that littered the site. Can you tell me why is this happening when upgrade to db.php of multidb 3.0.3 from 3.0.2? Thanks..