https://github.com/wildfly/wildfly-core/commit/f5c516f2#diff-dc2038399fc72656590c09fe73305791R151 assumes that the result transformer for the host request is appropriate for use with the subsequent requests to that host's servers during domain rollout.

That's a shaky supposition, as the server ops generated from a host request have no fixed relationship to the host request itself. Alignment is the norm but not a rule. In particular it can faill apart with composite ops where some steps in the composite are not relevant to all hosts.

Without this extra transformation, test at [1] fails. This indicates the server op is not getting the transformation registered at [2] applied. But if it's not getting the result transformation applied, wouldn't that mean relevant operation transformation isn't being applied as well?

[1] https://github.com/wildfly/wildfly-core/blob/master/testsuite/domain/src/test/java/org/jboss/as/test/integration/domain/suites/OperationTransformationTestCase.java#L226

[2] https://github.com/wildfly/wildfly-core/blob/master/testsuite/domain/src/test/java/org/jboss/as/test/integration/domain/extension/VersionedExtension2.java#L108