SSRS 2008 SP1 seems to have broken the Group variables capability

Question

I have used group variable to set the rows in my tablix to display alternating colors successfully in SSRS2008, however, since installing SP-1, group variable does not seem to work. I entered the same groups variable, in the same order on a newer report, and I get no error on running but my report does not display the way I set it to. One of the things I noticed is that when I set the group variable, it does not appear in the text box expression window in the variable tree(as it did before I installed SP-1)also if I do manually type an expression with the group variable i set, it appears underlined in red with the message "Unknown Collection Member". Which to me says VS is not recognizing the variable when I create it.