diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index 0f7810a2a758e590d762f84e935a40af652dde2f..54093096603c53189ce421766aaf9cd82e389ea7 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -11,6 +11,8 @@ Unreleased
 
 Fixed
 ~~~~~
+* In some cases, pages showing the count of extra marks and lessons with custom excuse types of
+  persons threw an error.
 * The redirection to generated class register PDF printouts did not work.
 
 `3.0b0`_ - 2022-02-28
diff --git a/aleksis/apps/alsijil/models.py b/aleksis/apps/alsijil/models.py
index b504a294164a6388099148fda5149091767577a7..615b28b360e661e2a5e2c784a10069de6c6a43bd 100644
--- a/aleksis/apps/alsijil/models.py
+++ b/aleksis/apps/alsijil/models.py
@@ -1,12 +1,14 @@
 from datetime import date
 from typing import Optional, Union
 from urllib.parse import urlparse
+from uuid import uuid4
 
 from django.db import models
 from django.db.models.constraints import CheckConstraint
 from django.db.models.query_utils import Q
 from django.urls import reverse
 from django.utils.formats import date_format
+from django.utils.text import slugify
 from django.utils.translation import gettext_lazy as _
 
 from calendarweek import CalendarWeek
@@ -66,7 +68,7 @@ class ExcuseType(ExtensibleModel):
 
     @property
     def count_label(self):
-        return f"{self.short_name}_count"
+        return f"excuse_type_{self.id}_count"
 
     class Meta:
         ordering = ["name"]
@@ -437,7 +439,7 @@ class ExtraMark(ExtensibleModel):
 
     @property
     def count_label(self):
-        return f"{self.short_name}_count"
+        return f"extra_mark_{self.id}_count"
 
     class Meta:
         ordering = ["short_name"]