Turn off autoescape for ikasan.body.txt
-{{ alert.labels.alertname }} {{ alert.labels.farm }} {{ alert.labels.instance }} {{ alert.labels.job }} {{ alert.status }}
+{% autoescape off %}{{ alert.labels.alertname }} {{ alert.labels.farm }} {{ alert.labels.instance }} {{ alert.labels.job }} {{ alert.status }}
{% for k,v in alert.annotations.items|dictsort:0 %}
{{ k }}: {{ v }}{% endfor %}
Prometheus: {{ alert.generatorURL }}
-Alert Manager: {{ externalURL }}
+Alert Manager: {{ externalURL }}{% endautoescape %}
