          self.assertQuerysetEqual(Animal.objects.exclude(tags__tag='fatty'), [
              "<Animal: Lion>"
          ])
  
          # If you delete an object with an explicit Generic relation, the related
          # objects are deleted when the source object is deleted.
          # Original list of tags:
          comp_func = lambda obj: (
 
</s> remove     Vegetable, Mineral, Gecko, Rock)
 </s> add     Vegetable, Mineral, Gecko, Rock, ManualPK)
        mpk.delete()
          self.assertQuerysetEqual(Animal.objects.exclude(tags__tag='fatty'), [
              "<Animal: Lion>"
          ])
        mpk.delete()
  
          # If you delete an object with an explicit Generic relation, the related
          # objects are deleted when the source object is deleted.
          # Original list of tags:
          comp_func = lambda obj: (
keep keep add keep keep keep keep keep
 Fixed #19939 -- generic relations + split_exclude regression

Added a test, the issue was already fixed (likely by the patch
for #19385). 
tests/generic_relations/tests.py