diff --git a/CHANGELOG.md b/CHANGELOG.md
index e862862eb..55a152fa5 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,7 @@ and this project adheres to
 ## Unreleased
 
 <!-- write down unreleased development here -->
+* fix normalisation of accompanying course requestor api (https://gitlab.com/champs-libres/departement-de-la-vendee/chill/-/issues/378)
 * [person] add a returnPath when clicking on some Person or ThirdParty badge (https://gitlab.com/champs-libres/departement-de-la-vendee/chill/-/issues/427)
 * [person] accompanying course work: fix on-the-fly update of thirdParty 
 * [on-the-fly] close modal only after validation
@@ -37,7 +38,7 @@ and this project adheres to
 * [parcours]: validation + message for closing parcours adjusted.
 * [household]: household composition double edit button replaced by a delete action (https://gitlab.com/champs-libres/departement-de-la-vendee/chill/-/issues/426)
 [fast_actions] improve fast-actions buttons override mechanism, fix https://gitlab.com/champs-libres/departement-de-la-vendee/accent-suivi-developpement/-/issues/413
-[homepage widget] add vue homepage_widget with asynchone loading, give a global view resume of the user concerned actions, notifications, etc.  
+[homepage widget] add vue homepage_widget with asynchone loading, give a global view resume of the user concerned actions, notifications, etc.
 * [person]: Comment on marital status is possible even if marital status is not defined (https://gitlab.com/champs-libres/departement-de-la-vendee/chill/-/issues/421)
 * [parcours]: In the list of person results the requestor is not displayed if defined as anonymous (https://gitlab.com/champs-libres/departement-de-la-vendee/chill/-/issues/424)
 * [bugfix]: modal closes and newly created person/thirdparty is selected when multiple persons/thirdparties are created through the modal (https://gitlab.com/champs-libres/departement-de-la-vendee/chill/-/issues/429)
@@ -45,7 +46,7 @@ and this project adheres to
 * [workflow][notification] improve how notifications and workflows are 'attached' to entities: contextual list, counter, buttons and vue modal
 * [AddAddress] disable multiselect search, and rely only on most pertinent Cities and Street computed backend
 * [fast_actions] improve fast-actions buttons override mechanism, fix https://gitlab.com/champs-libres/departement-de-la-vendee/accent-suivi-developpement/-/issues/413
-* [homepage widget] add vue homepage_widget with asynchone loading, give a global view resume of the user concerned actions, notifications, etc.  
+* [homepage widget] add vue homepage_widget with asynchone loading, give a global view resume of the user concerned actions, notifications, etc.
 
 ### test release 2021-01-31
 
@@ -94,7 +95,7 @@ and this project adheres to
 * [popover] add popover html popup mechanism (used by workflow breadcrumb)
 * [templates] improve updatedBy macro in item metadatas
 * [parcours]: bug fix when comment is pinned all other comments remain in the collection (https://gitlab.com/champs-libres/departement-de-la-vendee/chill/-/issues/385)
-* [workflow] 
+* [workflow]
   * add My workflow section with my opened subscriptions
   * apply workflow on documents, accompanyingCourseWork and Evaluations
 * [wopi-link] a new vue component allow to open wopi link in a fullscreen chill-themed modal
diff --git a/src/Bundle/ChillMainBundle/Serializer/Normalizer/DiscriminatedObjectDenormalizer.php b/src/Bundle/ChillMainBundle/Serializer/Normalizer/DiscriminatedObjectDenormalizer.php
index 77f14c8da..76ba52a3d 100644
--- a/src/Bundle/ChillMainBundle/Serializer/Normalizer/DiscriminatedObjectDenormalizer.php
+++ b/src/Bundle/ChillMainBundle/Serializer/Normalizer/DiscriminatedObjectDenormalizer.php
@@ -12,6 +12,7 @@ declare(strict_types=1);
 namespace Chill\MainBundle\Serializer\Normalizer;
 
 use LogicException;
+use Symfony\Component\Serializer\Exception\NotNormalizableValueException;
 use Symfony\Component\Serializer\Exception\RuntimeException;
 use Symfony\Component\Serializer\Normalizer\ContextAwareDenormalizerInterface;
 use Symfony\Component\Serializer\Normalizer\DenormalizerAwareInterface;
@@ -44,7 +45,7 @@ class DiscriminatedObjectDenormalizer implements ContextAwareDenormalizerInterfa
             if ($this->denormalizer->supportsDenormalization($data, $localType, $format)) {
                 try {
                     return $this->denormalizer->denormalize($data, $localType, $format, $context);
-                } catch (RuntimeException $e) {
+                } catch (RuntimeException|NotNormalizableValueException $e) {
                     $lastException = $e;
                 }
             }
diff --git a/src/Bundle/ChillPersonBundle/Controller/AccompanyingCourseApiController.php b/src/Bundle/ChillPersonBundle/Controller/AccompanyingCourseApiController.php
index c66488869..3da40db4c 100644
--- a/src/Bundle/ChillPersonBundle/Controller/AccompanyingCourseApiController.php
+++ b/src/Bundle/ChillPersonBundle/Controller/AccompanyingCourseApiController.php
@@ -16,6 +16,7 @@ use Chill\MainBundle\Entity\Scope;
 use Chill\MainBundle\Entity\User;
 use Chill\MainBundle\Serializer\Model\Collection;
 use Chill\MainBundle\Serializer\Model\Counter;
+use Chill\MainBundle\Serializer\Normalizer\DiscriminatedObjectDenormalizer;
 use Chill\PersonBundle\AccompanyingPeriod\Suggestion\ReferralsSuggestionInterface;
 use Chill\PersonBundle\Entity\AccompanyingPeriod;
 use Chill\PersonBundle\Entity\AccompanyingPeriod\AccompanyingPeriodWork;
@@ -234,17 +235,19 @@ final class AccompanyingCourseApiController extends ApiController
             $requestor = null;
             $exceptions = [];
 
-            foreach ([Person::class, ThirdParty::class] as $class) {
-                try {
-                    $requestor = $this->getSerializer()
-                        ->deserialize($request->getContent(), $class, $_format, []);
-                } catch (RuntimeException $e) {
-                    $exceptions[] = $e;
-                }
+            try {
+                $requestor = $this->getSerializer()->deserialize(
+                    $request->getContent(),
+                    '@multi',
+                    $_format,
+                    [DiscriminatedObjectDenormalizer::ALLOWED_TYPES => [Person::class, ThirdParty::class]]
+                );
+            } catch (RuntimeException $e) {
+                $exceptions[] = $e;
             }
 
             if (null === $requestor) {
-                throw new BadRequestException('Could not find any person or requestor', 0, $exceptions[0]);
+                throw new BadRequestException('Could not find any person or thirdparty', 0, null);
             }
 
             $accompanyingPeriod->setRequestor($requestor);