Running across this bug is a bit odd, because I wasn’t aware of any assertions that I was making, but this was the offending code:

{% if display_type == 'ts' %}
<script src="/static/highstock.js" type="text/javascript">
</script>
{% else if display_type == 'avg' %}
<script src="/static/highcharts.js" type="text/javascript">
</script>
{% endif %}

The above code ended up causing an AssertionError: No exception supplied. The idea was to do a conditional JavaScript import, but the problem actually ended up being in the Django template syntax. The correction was to replace the “else if” with an “elif”. Rookie mistake! Corrected code:

{% if display_type == 'ts' %}
<script src="/static/highstock.js" type="text/javascript">
</script>
{% elif display_type == 'avg' %}
<script src="/static/highcharts.js" type="text/javascript">
</script>
{% endif %}