"Must join group" not fixed in 6.x-2.x-dev or 6.x-2.0-rc3

*Description:
When logged in as a user belonging to the group or as the group's designated admin, I get the "You must join a group before posting on this web site." error.
NOTE: I did a clean install and set up again with no extra modules and still got the same error.

NOTE: I am not using Advanced Forum.

*Repeatable: Always

Does not happen to user=admin.

*Steps to repeat:

Log in as member of a group, try to post a forum topic.

*Expected Results:
New forum topic is posted and readable by all group members.

*Actual Results:
"You must join a group before posting on this web site." error message and no topic is saved.

*Detail & Proposed solution:
???
Wish I knew.