Member of the Event Log Readers group removed by System.

Hello,

I add a new member to the Event Log Readers group but the account is removed by System and I am unable to find the cause.  This only seems to be happening in one of my domains.  I have found the event id 4733 that states system but I am not sure why its doing this.  How do I get a membership to stick to this group?

The Domain Controllers are 2012 R2.

Thanks!

Shawn