• Import the attached tracker
• disable the workflow
• create an artifact with field "sb" value "none"
• reactivate the workflow
• try to update the value of "sb" field via REST
• observe the error

( ! ) Fatal error: Call to a member function getId() on a non-object in /usr/share/tuleap/plugins/tracker/include/Tracker/FormElement/Tracker_FormElement_Field_List.class.php on line 669Call Stack#TimeMemoryFunctionLocation10.0000659128{main}( )../index.php:020.17814768320Luracast\Restler\Restler->handle( )../index.php:8230.21394903872Luracast\Restler\Restler->call( )../Restler.php:30440.21475059512ReflectionMethod->invokeArgs( )../Restler.php:102450.21475059552Tuleap\Tracker\REST\v1\ArtifactsResource->putId( )../Restler.php:102460.23707886344Tracker_REST_Artifact_ArtifactUpdater->update( )../ArtifactsResource.class.php:17770.247310538256Tracker_Artifact->createNewChangeset( )../ArtifactUpdater.class.php:4180.248410686616Tracker_Artifact_Changeset_NewChangesetCreatorBase->create( )../Tracker_Artifact.class.php:102290.248510686744Tracker_Artifact_Changeset_NewChangesetCreatorBase->validateNewChangeset( )../NewChangesetCreatorBase.class.php:79100.248510686744Tracker_Artifact_Changeset_FieldsValidator->validate( )../NewChangesetCreatorBase.class.php:214110.285711539872Tracker_Artifact_Changeset_NewChangesetFieldsValidator->validateField( )../FieldsValidator.class.php:49120.285711539920Tracker_FormElement_Field->validateFieldWithPermissionsAndRequiredStatus( )../NewChangesetFieldsValidator.class.php:44130.286111541832Tracker_FormElement_Field->validateField( )../Tracker_FormElement_Field.class.php:910140.286111541880Tracker_FormElement_Field_List->isValid( )../Tracker_FormElement_Field.class.php:955150.286111541880Tracker_FormElement_Field_List->validate( )../Tracker_FormElement_Field_List.class.php:1283