Could you please change the text in the warning section from:
Setting the JAVA_OPTS environment variable will redefine the default values of the JAVA_OPTS environment variable. This may break the startup of JBoss EAP.
to:
Setting the JAVA_OPTS environment variable will redefine the default values from standalone.conf. This may break the startup of JBoss EAP.
Book: Configuration Guide
Revision: 8062923