Hi @howdy_mcgee
Greetings and thanks for posting on the forums.
I got the same warning message on my test site when i try to filter memberhsip members by status( Active / Inactive ) therefore i have notified the plugin developer to fix it.
This is a simple PHP warning, it is nothing to worry about but you can fix this warning message by making changes in the following Membership plugin file on line number 142
Membership plugin file:
membership/membershipincludes/classes/class.membersearch.php
Before Editing:
$sql = $wpdb->prepare( "SELECT user_id FROM " . $wpdb->usermeta . " WHERE meta_key = '" . membership_db_prefix($wpdb, 'membership_active', false) . "' AND meta_value = 'no'" );
After Editing:
$sql = "SELECT user_id FROM " . $wpdb->usermeta . " WHERE meta_key = '" . membership_db_prefix($wpdb, 'membership_active', false) . "' AND meta_value = 'no'";
Note: You are making changes in the plugin file and these changes will be overwritten and lost when you update the plugin and you will have to make these again after plugin updation.
Have a great day!
Cheers,
Vinod Dalvi