No. FreeFlow Output Manager is not affected. You can find the state of compliance as it relates to the Log4J issue for all Xerox products by refering the Xerox Special Bulletin Regarding CVE-2021-44228 on the Xerox Security website at https://security.business.xerox.com/en-us/documents/bulletins/
The Bulletin is updated daily so please check regularly.
Is FreeFlow Output Manager affected by the Log4J vulnerability like FreeFlow Core is? I can't find anything on the subject for this product. https://logging.apache.org/log4j/2.x/security.html