diff --git a/templates/form_post.html b/templates/form_post.html
index 1d0267e9f..71882c8ab 100644
--- a/templates/form_post.html
+++ b/templates/form_post.html
@@ -15,7 +15,7 @@ Please see LICENSE files in the repository root for full details.
     </div>
   </header>
 
-  <form method="post" class="flex flex-col"{% if redirect_uri %} action="{{ redirect_uri }}"{% endif %}>
+  <form method="post" class="flex flex-col"{% if redirect_uri is not none %} action="{{ redirect_uri }}"{% endif %}>
     {% for key, value in params|items %}
       <input type="hidden" name="{{ key }}" value="{{ value }}" />
     {% endfor %}
diff --git a/templates/pages/index.html b/templates/pages/index.html
index b8a0d7547..3ef8ea51b 100644
--- a/templates/pages/index.html
+++ b/templates/pages/index.html
@@ -19,7 +19,7 @@ Please see LICENSE files in the repository root for full details.
       </div>
     </header>
 
-    {% if current_session %}
+    {% if current_session is not none %}
       <p class="cpd-text-body-md-regular">
         {{ _("mas.navbar.signed_in_as", username=current_session.user.username) }}
       </p>
diff --git a/templates/pages/upstream_oauth2/do_register.html b/templates/pages/upstream_oauth2/do_register.html
index 2a57a6aca..f57564c43 100644
--- a/templates/pages/upstream_oauth2/do_register.html
+++ b/templates/pages/upstream_oauth2/do_register.html
@@ -26,7 +26,7 @@ Please see LICENSE files in the repository root for full details.
         </p>
       </div>
     </header>
-  {% elif upstream_oauth_provider.human_name %}
+  {% elif upstream_oauth_provider.human_name is not none %}
     <header class="page-heading">
       <div class="icon">
         {{ icon.user_profile_solid() }}
@@ -55,9 +55,9 @@ Please see LICENSE files in the repository root for full details.
     </header>
   {% endif %}
 
-  {% if upstream_oauth_provider.human_name %}
+  {% if upstream_oauth_provider.human_name is not none %}
     <section class="upstream-oauth2-provider-account">
-      {% if upstream_oauth_provider.brand_name %}
+      {% if upstream_oauth_provider.brand_name is not none %}
         {{ logo(brand=upstream_oauth_provider.brand_name, class="brand") }}
       {% else %}
         {{ icon.user_profile() }}
@@ -67,7 +67,7 @@ Please see LICENSE files in the repository root for full details.
         <h3 class="provider">
           {{- _("mas.upstream_oauth2.register.provider_name", human_name=upstream_oauth_provider.human_name) -}}
         </h3>
-        {% if upstream_oauth_link.human_account_name %}
+        {% if upstream_oauth_link.human_account_name is not none %}
           <p class="account">
             {{- upstream_oauth_link.human_account_name -}}
           </p>
@@ -147,7 +147,7 @@ Please see LICENSE files in the repository root for full details.
           <input {{ field.attributes(f) }} class="cpd-text-control" type="text" value="{{ imported_display_name }}" readonly />
 
           <div class="cpd-form-message cpd-form-help-message">
-            {% if upstream_oauth_provider.human_name %}
+            {% if upstream_oauth_provider.human_name is not none %}
               {{- _("mas.upstream_oauth2.register.imported_from_upstream_with_name", human_name=upstream_oauth_provider.human_name) -}}
             {% else %}
               {{- _("mas.upstream_oauth2.register.imported_from_upstream") -}}