diff --git a/_config.yml b/_config.yml
index 9693eaf2..4ab298be 100755
--- a/_config.yml
+++ b/_config.yml
@@ -4,6 +4,10 @@ future: false # Workaround for SeaGL/seagl.github.io#170
timezone: America/Los_Angeles
markdown: kramdown
highlighter: rouge
+liquid:
+ error_mode: strict
+ strict_filters: true
+ strict_variables: true
# Allowed plugins: https://pages.github.com/versions/
plugins: &plugins
diff --git a/_includes/header.html b/_includes/header.html
index bf6c7030..913236e2 100644
--- a/_includes/header.html
+++ b/_includes/header.html
@@ -1,3 +1,6 @@
+{% comment %} Workaround for https://github.com/Shopify/liquid/issues/1034 {% endcomment %}
+{% assign nav = nil %}{% if page contains "nav" %}{% assign nav = page.nav %}{% endif %}
+
{% assign sponsor_year = site.sponsor-years | last %}
diff --git a/_layouts/archive/conference.html b/_layouts/archive/conference.html
index b6133238..c204a15b 100644
--- a/_layouts/archive/conference.html
+++ b/_layouts/archive/conference.html
@@ -34,14 +34,14 @@
{{ day.name }}
{{ session.title }}
- {% if session.keynote %}
+ {% if session contains 'keynote' and session.keynote %}
Keynote
{% endif %}
{% for presenter in session.presenters %}
- {{ presenter.name }}{% if presenter.affiliation %}, {{ presenter.affiliation }}{% endif %}
+ {{ presenter.name }}{% if presenter contains 'affiliation' %}, {{ presenter.affiliation }}{% endif %}
{% endfor %}
diff --git a/_layouts/archive/session.html b/_layouts/archive/session.html
index b7ac48ae..8ea273c0 100644
--- a/_layouts/archive/session.html
+++ b/_layouts/archive/session.html
@@ -8,7 +8,7 @@
{% if session.resources %}
- {% if session.resources.internet_archive_identifier %}
+ {% if session.resources contains 'internet_archive_identifier' %}