WildFly main is currently seeing failures in the following tests when running the CDI TCK on Java 21:

CDI TCK failure:

ManagedBeanTypesTest>Arquillian.run:138->testGenericHierarchyBeanTypes:80 Set [class org.jboss.cdi.tck.tests.definition.bean.types.Flock, class java.lang.Object, interface java.util.SequencedCollection<org.jboss.cdi.tck.tests.definition.bean.types.Vulture<java.lang.Integer>>, java.util.List<org.jboss.cdi.tck.tests.definition.bean.types.Vulture<java.lang.Integer>>, interface java.util.Collection<org.jboss.cdi.tck.tests.definition.bean.types.Vulture<java.lang.Integer>>, interface java.lang.Iterable<org.jboss.cdi.tck.tests.definition.bean.types.Vulture<java.lang.Integer>>] (6) does not match array [class java.lang.Object, class org.jboss.cdi.tck.tests.definition.bean.types.Flock, java.util.List<org.jboss.cdi.tck.tests.definition.bean.types.Vulture<java.lang.Integer>>, java.util.Collection<org.jboss.cdi.tck.tests.definition.bean.types.Vulture<java.lang.Integer>>, java.lang.Iterable<org.jboss.cdi.tck.tests.definition.bean.types.Vulture<java.lang.Integer>>] (5)

See pull requests:
https://github.com/jakartaee/cdi-tck/pull/514
https://github.com/jakartaee/cdi-tck/pull/515

https://github.com/jakartaee/cdi-tck/pull/513 is now closed as being already addressed by the two above pull requests. Of interest still though may be this comment in 513:

Probably because of this? https://github.com/weld/core/blob/master/jboss-tck-runner/pom.xml#L364-L376
In Weld you can use -Dcdi.tck.suite.xml.file to change the xml file used.