The metrics subsystem in standalone-openshift.xml in the EAP images uses:

<param name="prefix" value="${wildfly.metrics.prefix:jboss}" />

Ultimate value without any property set being 'jboss'. But the various config files in zip still use 'wildfly'.

<param name="prefix" value="${wildfly.metrics.prefix:wildfly}" />

This is a missing 'eap-ization' change in wildfly-to-product. It wasn't noticed up to now because these zip configs were never distributed. The intended setting is shown in the commit bringing in the feature: https://github.com/jboss-container-images/jboss-eap-modules/commit/21e2be196616d32c8089a821bfd047e6c0cc2798#diff-dc247878a67453dbab33fe2b566af9d2

This shows the relevant spots in the code:

$ git grep metrics.prefix
galleon-pack/src/main/resources/feature_groups/metrics.xml: <param name="prefix" value="${wildfly.metrics.prefix:wildfly}" />
microprofile/metrics-smallrye/src/main/resources/subsystem-templates/microprofile-metrics-smallrye.xml: prefix="${wildfly.metrics.prefix:wildfly}" />

There's also this but it doesn't need changing as what particular value the low level test of the subsystem management code uses does not matter.:

microprofile/metrics-smallrye/src/test/resources/org/wildfly/extension/microprofile/metrics/subsystem_2_0.xml: prefix="${wildfly.metrics.prefix:wildfly}"/>