Given that I have a hierarchy between PI and Iteration, and that, during Iteration creation inside a I PI select a parent as suggested by the interface, even if it is the parent that will be normally automatically set by the creation process, I end up with this error in the logs:

Tuleap\ProgramManagement\Adapter\Events\ProgramIncrementUpdateEventProxy::logInvalidData plugins/program_management/include/Adapter/Events/ProgramIncrementUpdateEventProxy.php:106
Tuleap\ProgramManagement\Adapter\Events\ProgramIncrementUpdateEventProxy::fromWorkerEvent plugins/program_management/include/program_managementPlugin.php:773
program_managementPlugin->workerEvent src/common/Event/EventManager.class.php:127
EventManager->eventManagerDispatch src/common/Plugin/PluginLoader.php:73
Tuleap\Plugin\PluginLoader->Tuleap\Plugin\{closure} src/common/Event/EventManager.class.php:116
EventManager->processEventOnListener src/common/Event/EventManager.class.php:146
EventManager->dispatch src/common/Queue/TaskWorker/TaskWorkerProcessCommand.php:72
Tuleap\Queue\TaskWorker\TaskWorkerProcessCommand->execute src/vendor/symfony/console/Command/Command.php:291
Symfony\Component\Console\Command\Command->run src/vendor/symfony/console/Application.php:998
Symfony\Component\Console\Application->doRunCommand src/vendor/symfony/console/Application.php:299
Symfony\Component\Console\Application->doRun src/common/CLI/Application.php:75
Tuleap\CLI\Application->doRun src/vendor/symfony/console/Application.php:171
Symfony\Component\Console\Application->run src/utils/tuleap.php:287

Invalid data given in payload, skipping program increment update for artifact #XXX, user #XXX and changeset #XXX (previous changeset id #XX)

Please do note that the error message is probably inconsistent. After some debug with @marieange it appears that the message is misleading and inappropriate.