The well known MySQL bug fix is a fix for the following SQL errors,

WordPress database error You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ' feed_id = 1, hash = 178e9c301b4781e2c7248ed115802291995cd2b6'' at line 2 for query SELECT * FROM `wp_wpo_campaign_post` WHERE campaign_id = 1, feed_id = 1, hash = '178e9c301b4781e2c7248ed115802291995cd2b6'  made by isDuplicate

And/Or

WordPress database error Unknown column 'hash' in 'field list' for query INSERT INTO wp_wpo_campaign_post (campaign_id, feed_id, , post_id, hash) VALUES ('1','1','4300','9b79457042fd10a210da6110ecfdbed0ed1d45c9') made by processItem

The problem is that MySQL doesn't like the commas in the multiple where clauses. You need to edit wpomatic.php

Find the isDuplicate() function

 function isDuplicate(&$campaign, &$feed, &$item)
{
global $wpdb;
$hash = $this->getItemHash($item);
$row = $wpdb->get_row("SELECT * FROM `{$this->db['campaign_post']}`
WHERE campaign_id = {$campaign->id}, feed_id = {$feed->id}, hash = '$hash' ");
return !! $row;
}

and replace with

 function isDuplicate(&$campaign, &$feed, &$item)
{
global $wpdb;
$hash = $this->getItemHash($item);
$row = $wpdb->get_row("SELECT * FROM `{$this->db['campaign_post']}`
WHERE campaign_id = {$campaign->id} and feed_id = {$feed->id} and hash = '$hash' ");
return !! $row;
}

Here's the previous fixes.

WP-O-Matic Cron Hangs

WP-o-Matic Upgrade Fix

Wordpress WP-O-Matic Duplicate Posts Fix

This is my modified wpomatic.php file -> Direct Download

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