Given a "Release" artifact from the agiledashboard template that has the following fields:

• burndown
• duration (integer)
• capacity (computed)
• remaining_effort (computed, field_id = 913)
• release number (string, required, field_id = 906)
• status (checkbox, required)

And given I created a new artifact using the REST route POST /artifacts and the following payload

{
    "tracker": {
        "id": 40
    },
    "values": [{
        "field_id": 906,
        "value": "test"
    }, {
        "field_id": 913,
        "manual_value": 1
    }]
}

When I access the artifact view for this new artifact, a fatal error is thrown:

 Fatal error: Call to a member function getValue() on a non-object in /usr/share/tuleap/plugins/tracker/include/Tracker/FormElement/Tracker_FormElement_Field_Burndown.class.php on line 843
Call Stack
#	Time	Memory	Function	Location
1	0.0000	662592	{main}( )	../index.php:0
2	0.1187	5362288	TrackerManager->process( )	../index.php:33
3	0.1188	5362544	TrackerManager->processSubElement( )	../TrackerManager.class.php:126
4	0.1335	8499624	Tracker_Artifact->process( )	../TrackerManager.class.php:88
5	0.1344	8638568	Tracker_Artifact_EditRenderer->display( )	../Tracker_Artifact.class.php:870
6	0.1351	8687984	Tracker_Artifact_EditAbstractRenderer->display( )	../EditRenderer.class.php:85
7	0.2778	8700944	Tracker_Artifact_ArtifactRenderer->display( )	../EditAbstractRenderer.class.php:43
8	0.3077	9244272	Tracker_Artifact_EditRenderer->fetchFormContent( )	../ArtifactRenderer.class.php:63
9	0.3142	10093744	Tracker_Artifact_EditRenderer->fetchView( )	../EditRenderer.class.php:102
10	0.3157	10210960	Tracker_Artifact_View_ViewCollection->fetchRequestedView( )	../EditRenderer.class.php:186
11	0.3158	10211368	Tracker_Artifact_View_Edit->fetch( )	../ViewCollection.class.php:38
12	0.3177	10366752	Tracker_Artifact_ReadOnlyRenderer->fetchFields( )	../Edit.class.php:68
13	0.3177	10367168	Tracker->fetchFormElementsReadOnly( )	../ReadOnlyRenderer.class.php:41
14	0.3531	13060888	Tracker_FormElement_Container->fetchArtifactReadOnly( )	../Tracker.class.php:364
15	0.3531	13061368	Tracker_FormElement_Container->fetchRecursiveArtifact( )	../Tracker_FormElement_Container.class.php:240
16	0.3531	13061448	Tracker_FormElement_Container->getContainerContent( )	../Tracker_FormElement_Container.class.php:252
17	0.3579	14325912	call_user_func_array ( )	../Tracker_FormElement_Container.class.php:293
18	0.3579	14326336	Tracker_FormElement_Field->fetchArtifactReadOnly( )	../Tracker_FormElement_Container.class.php:293
19	0.3587	14327968	Tracker_FormElement_Field->fetchArtifactValueForWebDisplay( )	../Tracker_FormElement_Field.class.php:377
20	0.3587	14327968	Tracker_FormElement_Field_Burndown->fetchArtifactValueReadOnly( )	../Tracker_FormElement_Field.class.php:575
21	0.3587	14328152	Tracker_FormElement_Field_Burndown->fetchBurndownCacheGenerationButton( )	../Tracker_FormElement_Field_Burndown.class.php:115
22	0.3595	14355616	Tracker_FormElement_Field_Burndown->areBurndownFieldsCorrectlySet( )	../Tracker_FormElement_Field_Burndown.class.php:147
23	0.3595	14355616	Tracker_FormElement_Field_Burndown->getBurndownDuration( )	../Tracker_FormElement_Field_Burndown.class.php:166