The issue was that I was always using the docker tag “:latest”. I don’t know why deployments worked for a couple of weeks but now it isn’t working anymore. My workaround is to use different tags now and put the new images into the app spec file like this:

doctl registry login
docker push $IMAGE_NAME

doctl apps spec get $DO_APP_ID > $SPEC_FILE

# Replace image in app spec
echo "Setting tag $TAG"
sed -i '' "s/tag: [a-z0-9]*$/tag: $TAG/g" app_spec.yml
doctl apps spec validate $SPEC_FILE

doctl apps update $DO_APP_ID --spec $SPEC_FILE