Well, as usually is the case – I figured it out right after posting…
in notifications.php,
Change Lines 16 and 17:
<td class="yes"><input type="radio" name="notifications[notification_group_documents_upload_member]" value="yes" <?php if ( !get_usermeta( $current_user->id,'notification_group_documents_upload_member') || 'yes' == get_usermeta( $current_user->id,'notification_group_documents_upload_member') ) { ?>checked="checked" <?php } ?>/></td>
<td class="no"><input type="radio" name="notifications[notification_group_documents_upload_member]" value="no" <?php if ( get_usermeta( $current_user->id,'notification_group_documents_upload_member') == 'no' ) { ?>checked="checked" <?php } ?>/></td>
To:
<td class="yes"><input type="radio" name="notifications[notification_group_documents_upload_member]" value="yes" <?php if ( get_usermeta( $current_user->id,'notification_group_documents_upload_member') == 'yes' ) { ?>checked="checked" <?php } ?>/></td>
<td class="no"><input type="radio" name="notifications[notification_group_documents_upload_member]" value="no" <?php if ( !get_usermeta( $current_user->id,'notification_group_documents_upload_member') || 'no' == get_usermeta( $current_user->id,'notification_group_documents_upload_member') ) { ?>checked="checked" <?php } ?>/></td>