Proxy model needs manager definition

[DiogoMarques29]

Hello,
I have a class with a custom manager defined by:
objects = PolymorphicManager.from_queryset(PointOfInterestQuerySet)()

The proxy model:

class PointOfInterestGlobalSummary(PointOfInterest):
    class Meta:
        proxy = True
        verbose_name = _('Dashboard - Global')
        verbose_name_plural = _('Dashboard - Global')

Running some queries:

>>> PointOfInterest.objects.all().count()
139534
>>> PointOfInterestGlobalSummary.objects.all().count()
0

The solution was to define the proxy model with a normal manager:
objects = models.Manager()
The queries:

>>> PointOfInterest.objects.all().count()
139534
>>> PointOfInterestGlobalSummary.objects.all().count()
139534

Is this normal behavior? If so, maybe we should add some documentation?

Cheers