Membership: "Cannot modify header" warning when Changing Password on Account Page

When a user tries to change their password using the "account" page, which is generated by Membership, the following warning is displayed and repeated about 17 times:

Warning: Cannot modify header information – headers already sent by (output started at /home2/tsb/public_html/wp-content/themes/genesis/lib/structure/header.php:48) in /home2/tsb/public_html/wp-includes/pluggable.php on line 679

The password change does go through, but I would like to figure out how to get rid of these annoying warnings.

Troubleshooting steps that I've tried, but have not fixed the issue:

1. Disabling all other plugins besides Membership.
2. Changing Themes.

Any ideas?