Creating LDAP security realm fails with cryptic error message

When creating an LDAP security realm via CLI, setup fails with cryptic error message.

For example, creating a dir-context works fine:
/subsystem=elytron/dir-context=exampleDC:add(url="ldap://127.0.0.1:10389",principal="uid=admin,ou=system",credential="secret")

But when creating an ldap-realm:
/subsystem=elytron/ldap-realm=exampleLR:add(dir-context=exampleDC,identity-mapping={search-base-dn="ou=Users,dc=jboss,dc=org",rdn-identifier="uid",user-password-mapper={from="userPassword"}})

It fails:
{
"outcome" => "failed",
"failure-description" => "WFLYCTL0158: Operation handler failed: java.lang.IllegalArgumentException",
"rolled-back" => true
}

Full log in wildfly:
14:11:03,368 ERROR [org.jboss.as.controller.management-operation] (management-handler-thread - 4) WFLYCTL0013: Operation ("add") failed - address: ([
("subsystem" => "elytron"),
("ldap-realm" => "exampleLR")
]): java.lang.IllegalArgumentException
at org.jboss.dmr.ModelValue.asBoolean(ModelValue.java:69)
at org.jboss.dmr.ModelNode.asBoolean(ModelNode.java:267)
at org.wildfly.extension.elytron.LdapRealmDefinition$UserPasswordCredentialMappingObjectDefinition.configure(LdapRealmDefinition.java:163)
at org.wildfly.extension.elytron.LdapRealmDefinition$RealmAddHandler.configureIdentityMapping(LdapRealmDefinition.java:420)
at org.wildfly.extension.elytron.LdapRealmDefinition$RealmAddHandler.performRuntime(LdapRealmDefinition.java:375)
at org.jboss.as.controller.AbstractAddStepHandler.performRuntime(AbstractAddStepHandler.java:337)
at org.jboss.as.controller.AbstractAddStepHandler$1.execute(AbstractAddStepHandler.java:151)
at org.jboss.as.controller.AbstractOperationContext.executeStep(AbstractOperationContext.java:940)
at org.jboss.as.controller.AbstractOperationContext.processStages(AbstractOperationContext.java:683)
at org.jboss.as.controller.AbstractOperationContext.executeOperation(AbstractOperationContext.java:382)
at org.jboss.as.controller.OperationContextImpl.executeOperation(OperationContextImpl.java:1363)
at org.jboss.as.controller.ModelControllerImpl.internalExecute(ModelControllerImpl.java:410)
at org.jboss.as.controller.ModelControllerImpl.execute(ModelControllerImpl.java:232)
at org.jboss.as.controller.remote.ModelControllerClientOperationHandler$ExecuteRequestHandler.doExecute(ModelControllerClientOperationHandler.java:213)
at org.jboss.as.controller.remote.ModelControllerClientOperationHandler$ExecuteRequestHandler.access$300(ModelControllerClientOperationHandler.java:136)
at org.jboss.as.controller.remote.ModelControllerClientOperationHandler$ExecuteRequestHandler$1$1.run(ModelControllerClientOperationHandler.java:157)
at org.jboss.as.controller.remote.ModelControllerClientOperationHandler$ExecuteRequestHandler$1$1.run(ModelControllerClientOperationHandler.java:153)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:422)
at org.jboss.as.controller.AccessAuditContext.doAs(AccessAuditContext.java:149)
at org.jboss.as.controller.remote.ModelControllerClientOperationHandler$ExecuteRequestHandler$1.execute(ModelControllerClientOperationHandler.java:153)
at org.jboss.as.protocol.mgmt.ManagementRequestContextImpl$1.doExecute(ManagementRequestContextImpl.java:70)
at org.jboss.as.protocol.mgmt.ManagementRequestContextImpl$AsyncTaskRunner.run(ManagementRequestContextImpl.java:160)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
at org.jboss.threads.JBossThread.run(JBossThread.java:320)