UniqueConstraint not working properly

[SilenceInside]

The new 3.15.0 release introduced a bug with validation unique constraint

add test case for drf tests

# test_validators.py
class UniqueConstraintModel(models.Model):
    race_name = models.CharField(max_length=100)
    position = models.IntegerField()
    global_id = models.IntegerField()
    fancy_conditions = models.IntegerField(null=True)

    # new field
    active = models.BooleanField(default=False)  
   
    class Meta:
        constraints = [
            models.UniqueConstraint(
                name="unique_constraint_model_global_id_uniq",
                fields=('global_id',),
            ),
            models.UniqueConstraint(
                name="unique_constraint_model_fancy_1_uniq",
                fields=('fancy_conditions',),
                condition=models.Q(global_id__lte=1)
            ),
            models.UniqueConstraint(
                name="unique_constraint_model_fancy_3_uniq",
                fields=('fancy_conditions',),
                condition=models.Q(global_id__gte=3)
            ),
            models.UniqueConstraint(
                name="unique_constraint_model_together_uniq",
                fields=('race_name', 'position'),
                condition=models.Q(race_name='example'),
            ),

            # new  UniqueConstraint
            models.UniqueConstraint( 
                name="unique_constraint_model_race_name_active",
                fields=('race_name',),
                condition=models.Q(active=True),
            )
        ]

class TestUniqueConstraintValidation(TestCase):
    ...

    def test_unique_race_name_active(self):
        self.instance.active = True
        self.instance.save()
        data = {'race_name': 'example', 'position': 5, 'fancy_conditions': self.instance.fancy_conditions, 'global_id': 5, 'active': False}
        serializer = UniqueConstraintSerializer(data=data)
        assert serializer.is_valid()

we have validation error:

{'race_name': [ErrorDetail(string='unique constraint model with this race name already exists.', code='unique')]}

In serializer data we have active=False, but under the hood drf make check:

UniqueConstraintModel.objects.filter(Q(active=True), race_name='example').exists()

Looks like a bug

p.s. I saw issues about UniqueTogether but I'm not sure if it's the same