diff --git a/src/Bundle/ChillPersonBundle/Tests/Validator/AccompanyingPeriod/ParticipationOverlapValidatorTest.php b/src/Bundle/ChillPersonBundle/Tests/Validator/AccompanyingPeriod/ParticipationOverlapValidatorTest.php
new file mode 100644
index 000000000..381a42578
--- /dev/null
+++ b/src/Bundle/ChillPersonBundle/Tests/Validator/AccompanyingPeriod/ParticipationOverlapValidatorTest.php
@@ -0,0 +1,108 @@
+<?php
+
+namespace Validator\AccompanyingPeriod;
+
+use Chill\PersonBundle\Entity\AccompanyingPeriod;
+use Chill\PersonBundle\Entity\Person;
+use Chill\PersonBundle\Templating\Entity\PersonRenderInterface;
+use Chill\PersonBundle\Validator\Constraints\AccompanyingPeriod\ParticipationOverlap;
+use Chill\PersonBundle\Validator\Constraints\AccompanyingPeriod\ParticipationOverlapValidator;
+use Chill\ThirdPartyBundle\Entity\ThirdParty;
+use Chill\ThirdPartyBundle\Templating\Entity\ThirdPartyRender;
+use Prophecy\Argument;
+use Prophecy\PhpUnit\ProphecyTrait;
+use Symfony\Component\Validator\Test\ConstraintValidatorTestCase;
+
+class ParticipationOverlapValidatorTest extends ConstraintValidatorTestCase
+{
+    use ProphecyTrait;
+
+    public function testNoViolation(): void
+    {
+        $constraint = $this->getConstraint();
+
+        $period = new AccompanyingPeriod();
+        $person1 = new Person();
+        $person2 = new Person();
+
+        $period->createParticipationFor($person1);
+        $period->createParticipationFor($person2);
+
+        $this->validator->validate($period->getParticipations(), $constraint);
+
+        $this->assertNoViolation();
+    }
+
+    public function testHasTwoParticipationsOverlaps(): void
+    {
+        $constraint = $this->getConstraint();
+
+        $period = new AccompanyingPeriod();
+        $person1 = new Person();
+        $reflectionPerson = new \ReflectionClass($person1);
+        $personId = $reflectionPerson->getProperty('id');
+        $personId->setAccessible(true);
+        $personId->setValue($person1, 1);
+        $person2 = new Person();
+
+        $period->createParticipationFor($person1);
+        $period->createParticipationFor($person1);
+        $period->createParticipationFor($person2);
+
+        $this->validator->validate($period->getParticipations(), $constraint);
+
+        $this->buildViolation('participation-overlaps')
+            ->setParameters([
+                '{{ start }}' => (new \DateTimeImmutable('today'))->format('d-m-Y'),
+                '{{ end }}' => null,
+                '{{ ids }}' => [null, null],
+                '{{ name }}' => 'person'
+            ])
+            ->assertRaised();
+    }
+
+    public function testHasTwoParticipationsButDoNotOverlaps(): void
+    {
+        $constraint = $this->getConstraint();
+
+        $period = new AccompanyingPeriod();
+        $person1 = new Person();
+        $reflectionPerson = new \ReflectionClass($person1);
+        $personId = $reflectionPerson->getProperty('id');
+        $personId->setAccessible(true);
+        $personId->setValue($person1, 1);
+        $person2 = new Person();
+
+        $participation1 = $period->createParticipationFor($person1);
+        $period->createParticipationFor($person1);
+        $participation1->setEndDate(new \DateTime('now'));
+        $period->createParticipationFor($person2);
+
+        $this->validator->validate($period->getParticipations(), $constraint);
+
+        $this->assertNoViolation();
+    }
+    protected function createValidator(): ParticipationOverlapValidator
+    {
+        $personRender = $this->prophesize(PersonRenderInterface::class);
+        $personRender->renderString(Argument::type(Person::class), [])
+            ->willReturn('person');
+        $thirdPartyRender = $this->prophesize(ThirdPartyRender::class);
+        $thirdPartyRender->renderString(Argument::type(ThirdParty::class), [])
+            ->willReturn('third-party');
+
+        return new ParticipationOverlapValidator(
+            $personRender->reveal(),
+            $thirdPartyRender->reveal()
+        );
+    }
+
+    public function getConstraint(): ParticipationOverlap
+    {
+        return new ParticipationOverlap(['message' => 'participation-overlaps']);
+    }
+
+
+
+
+}
diff --git a/src/Bundle/ChillPersonBundle/Validator/Constraints/AccompanyingPeriod/ParticipationOverlapValidator.php b/src/Bundle/ChillPersonBundle/Validator/Constraints/AccompanyingPeriod/ParticipationOverlapValidator.php
index 9c9991a1a..527bb43cb 100644
--- a/src/Bundle/ChillPersonBundle/Validator/Constraints/AccompanyingPeriod/ParticipationOverlapValidator.php
+++ b/src/Bundle/ChillPersonBundle/Validator/Constraints/AccompanyingPeriod/ParticipationOverlapValidator.php
@@ -61,9 +61,9 @@ class ParticipationOverlapValidator extends ConstraintValidator
                 throw new UnexpectedTypeException($participation, AccompanyingPeriodParticipation::class);
             }
 
-            $personId = $participation->getPerson()->getId();
+            $hashPerson = spl_object_hash($participation->getPerson());
 
-            $participationList[$personId][] = $participation;
+            $participationList[$hashPerson][] = $participation;
         }
 
         foreach ($participationList as $group) {
diff --git a/src/Bundle/ChillThirdPartyBundle/Form/ChoiceLoader/ThirdPartyChoiceLoader.php b/src/Bundle/ChillThirdPartyBundle/Form/ChoiceLoader/ThirdPartyChoiceLoader.php
index 5c990c9ad..3b5931aa6 100644
--- a/src/Bundle/ChillThirdPartyBundle/Form/ChoiceLoader/ThirdPartyChoiceLoader.php
+++ b/src/Bundle/ChillThirdPartyBundle/Form/ChoiceLoader/ThirdPartyChoiceLoader.php
@@ -23,6 +23,8 @@ use function in_array;
 
 /**
  * Lazy load third parties.
+ *
+ * @deprecated As the PickThirdPartyType is deprecated, this should not be in use
  */
 class ThirdPartyChoiceLoader implements ChoiceLoaderInterface
 {
@@ -57,7 +59,7 @@ class ThirdPartyChoiceLoader implements ChoiceLoaderInterface
         $choices = [];
 
         foreach ($values as $value) {
-            if (empty($value)) {
+            if (null === $value || '' === $value) {
                 continue;
             }
 
diff --git a/src/Bundle/ChillThirdPartyBundle/Form/Type/PickThirdPartyType.php b/src/Bundle/ChillThirdPartyBundle/Form/Type/PickThirdPartyType.php
index 259fb63f4..ed4b3c1e7 100644
--- a/src/Bundle/ChillThirdPartyBundle/Form/Type/PickThirdPartyType.php
+++ b/src/Bundle/ChillThirdPartyBundle/Form/Type/PickThirdPartyType.php
@@ -29,6 +29,10 @@ use function array_merge;
 use function count;
 use function is_array;
 
+/**
+ * @deprecated use the @link{PickThirdPartyDynamicType::class}
+ * @note do remove ThirdPartyChoiceLoader if this class is removed
+ */
 class PickThirdPartyType extends AbstractType
 {
     /**
diff --git a/src/Bundle/ChillThirdPartyBundle/Repository/ThirdPartyRepository.php b/src/Bundle/ChillThirdPartyBundle/Repository/ThirdPartyRepository.php
index 134957c0f..76e15ef17 100644
--- a/src/Bundle/ChillThirdPartyBundle/Repository/ThirdPartyRepository.php
+++ b/src/Bundle/ChillThirdPartyBundle/Repository/ThirdPartyRepository.php
@@ -180,7 +180,7 @@ final class ThirdPartyRepository implements ObjectRepository
         if (array_key_exists('name', $terms) || array_key_exists('_default', $terms)) {
             $term = $terms['name'] ?? $terms['_default'];
 
-            if (empty($term)) {
+            if (null === $term || '' === $term) {
                 return;
             }
             $qb->andWhere($qb->expr()->like('UNACCENT(LOWER(tp.name))', 'UNACCENT(LOWER(:name))'));