Reproduction steps of the issue:
1. Create a new reference with a description like "plugin_aaaaa:notfound_desc_key"
2. Use this reference in a follow up comments of an artifact


Trace:
Exception: Missing translation for crash_desc_key:aaaa in /usr/share/tuleap/src/common/reference/ReferenceManager.class.php on line 529
Call Stack
# Time Memory Function Location
1 0.0000 399192 {main}( ) .../index.php:0
2 0.0083 2442128 Tuleap\Request\FrontRouter->route( ) .../index.php:46
3 0.0104 2949424 Tuleap\Request\FrontRouter->routeHandler( ) .../FrontRouter.php:103
4 0.0288 4421616 Tuleap\Tracker\TrackerPluginDefaultController->process( ) .../FrontRouter.php:235
5 0.0288 4421648 TrackerManager->process( ) .../TrackerPluginDefaultController.php:45
6 0.0289 4421688 TrackerManager->processSubElement( ) .../TrackerManager.class.php:165
7 0.0366 4878296 Tracker_Artifact->process( ) .../TrackerManager.class.php:109
8 0.0406 4993248 Tracker_Artifact_ReadOnlyRenderer->display( ) .../Tracker_Artifact.class.php:836
9 0.0429 5029792 Tracker_Artifact_ReadOnlyRenderer->display( ) .../EditRenderer.class.php:87
10 0.0447 4990800 Tracker_Artifact_ReadOnlyRenderer->display( ) .../EditAbstractRenderer.class.php:51
11 0.0961 6658224 Tracker_Artifact_ReadOnlyRenderer->fetchFormContent( ) .../ArtifactRenderer.class.php:61
12 0.1193 6959104 Tracker_Artifact_ReadOnlyRenderer->fetchView( ) .../EditRenderer.class.php:105
13 0.1415 7851568 Tracker_Artifact_View_ViewCollection->fetchRequestedView( ) .../EditRenderer.class.php:161
14 0.1416 7851728 Tracker_Artifact_View_Edit->fetch( ) .../ViewCollection.class.php:38
15 0.1590 8243240 Tracker_Artifact_View_Edit->fetchFollowUps( ) .../Edit.class.php:77
16 0.1640 8294816 Tracker_Artifact_View_Edit->fetchCommentContent( ) .../Edit.class.php:114
17 0.1643 8307360 Tracker_Artifact_Changeset->fetchFollowUp( ) .../Edit.class.php:183
18 0.1653 8311808 Tracker_Artifact_Changeset->getFollowupContent( ) .../Tracker_Artifact_Changeset.class.php:238
19 0.1653 8311808 Tracker_Artifact_Changeset_Comment->fetchFollowUp( ) .../Tracker_Artifact_Changeset.class.php:199
20 0.1653 8312192 Tracker_Artifact_Changeset_Comment->getPurifiedBodyForHTML( ) .../Tracker_Artifact_Changeset_Comment.class.php:170
21 0.1653 8312192 Tracker_Artifact_Changeset_Comment->purifyBody( ) .../Tracker_Artifact_Changeset_Comment.class.php:122
22 0.1653 8312192 Codendi_HTMLPurifier->purify( ) .../Tracker_Artifact_Changeset_Comment.class.php:130
23 0.1654 8312352 Codendi_HTMLPurifier->purify( ) .../Codendi_HTMLPurifier.class.php:250
24 0.1654 8312376 Codendi_HTMLPurifier->insertReferences( ) .../Codendi_HTMLPurifier.class.php:238
25 0.1656 8390912 ReferenceManager->insertReferences( ) .../Codendi_HTMLPurifier.class.php:318
26 0.1657 8391432 preg_replace_callback ( ) .../ReferenceManager.class.php:554
27 0.1657 8392608 ReferenceManager->{closure:/usr/share/tuleap/src/common/reference/ReferenceManager.class.php:547-553}( ) .../ReferenceManager.class.php:554
28 0.1790 8521992 ReferenceManager->buildLinkForReference( ) .../ReferenceManager.class.php:552
29 0.1791 8521992 ReferenceManager->getTranslatedDescription( ) .../ReferenceManager.class.php:511