This is working correctly on our test site and on your testforum1.site. I don't have access to your other test, so I can't say why this is happening. There have been no changes to the style importer since beta 1. finalupgrade.php does this, but have you tried rebuilding your styles?
Did step #5 complete successfully on finalupgrade.php when you upgraded?
EDIT: My apologies. Yesterday we wrote a new tool for automatically generating all the install XML files more efficiently. It looks like it left out the vB4 stylevar definitions.
Fixed in the current ZIP. Please download and rerun finalupgrade.php?step=5.