As some said in this thread, it seems to be linked to redundant failover. 2 other threads I think are worth checking out.
An IA rep responded in this thread
Some of the messages indicate that it started after an upgrade on the system. If you can safely do it, I would break redundancy, upgrade both systems to the same version and then re-establish redundancy and see if it's fixed. You can also contact support and have them look at the backend db. Of course, make a gateway backup before trying this.