WPMU Membership Plugin Reply/Comment Conflict with BuddyPress

Hello - on http://www.suspicious0bservers.org in the Forums section we use BuddyPress. We also use WPMU Membership to have a single paid content "premium member" subscription option. When you pay and register for the premium membership you are granted access to various pages with media content protected for members only. In addition, we have a BuddyPress Group that is visible only to paying members.

Our issue is that there seems to be some kind of conflict between Memberships and BP in terms of the Comment and Reply functionality in the members only Group. EVERYTHING works fine except a paying member can not reply or comment to existing update posts (however they can post a new update to the private members only group).

For example: a paying member is not able to comment on someones post - ie. someone writes "hey this is a great idea..." and posts it to the Group feed I am not able to comment and say "yes it is!". I have to post a new update to the feed such as "@person yes it is!".

For both free and paying members the reply and comment ability works properly in ALL the Groups that are openly public (no paying membership required). However, once in the paid members only group, the comment/reply functionality fails and one can only post a new update to the feed.

Is this something to do with how we've set up the Access Levels? What we've done is set Free and Visitor/Stranger access levels to the Negative Rule "do not allow access to the members only group" - while for the paying members we've set their Access Level rules to nothing, ie. have not added any rules whatsoever so that they are able to still do all the things the Free and Visitor/Stranger accounts can do.

Thank you very much for your assistance.