Print view fails sometimes with KeyError

Traceback (most recent call last):
 File "/srv/aleksis/envs/production/lib/python3.9/site-packages/django/core/handlers/exception.py", line 47, in inner
   response = get_response(request)
 File "/srv/aleksis/envs/production/lib/python3.9/site-packages/django/core/handlers/base.py", line 181, in _get_response
   response = wrapped_callback(request, *callback_args, **callback_kwargs)
 File "/srv/aleksis/envs/production/lib/python3.9/site-packages/rules/contrib/views.py", line 231, in _wrapped_view
   return view_func(request, *args, **kwargs)
 File "/srv/aleksis/envs/production/lib/python3.9/site-packages/aleksis/apps/alsijil/views.py", line 739, in full_register_group
   person.filtered_notes = sorted_personal_notes["person"][person.pk]