diff --git a/Dockerfile b/Dockerfile
index 4810bff..235d347 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -6,7 +6,7 @@ RUN npm install && \
 
 FROM python:3.10.9-alpine
 
-ENV VERSION_NUMBER 0.1.2-10-g97467c7
+ENV VERSION_NUMBER 0.1.2-11-g025ea0d
 ENV PROD 1
 
 RUN apk add \
diff --git a/src/web/tracker/views.py b/src/web/tracker/views.py
index 8418537..0e3e08b 100644
--- a/src/web/tracker/views.py
+++ b/src/web/tracker/views.py
@@ -56,7 +56,7 @@ def list_sessions(request, purchase_id=None):
         dataset = Session.objects.all().order_by("timestamp_start")
 
     for session in dataset:
-        if session.timestamp_end == None and session.duration_manual == None:
+        if session.timestamp_end == None and session.duration_manual.seconds == 0:
             session.timestamp_end = datetime.now(ZoneInfo(settings.TIME_ZONE))
             session.unfinished = True