diff --git a/docs_user/modules/proc_adopting-compute-services-to-the-data-plane.adoc b/docs_user/modules/proc_adopting-compute-services-to-the-data-plane.adoc
index 9ad73f727..18d77b8c4 100644
--- a/docs_user/modules/proc_adopting-compute-services-to-the-data-plane.adoc
+++ b/docs_user/modules/proc_adopting-compute-services-to-the-data-plane.adoc
@@ -455,7 +455,7 @@ endif::[]
            ---
            {% set mtu_list = [ctlplane_mtu] %}
            {% for network in nodeset_networks %}
-           {{ mtu_list.append(lookup('vars', networks_lower[network] ~ '_mtu')) }}
+           {% set _ = mtu_list.append(lookup('vars', networks_lower[network] ~ '_mtu')) %}
            {%- endfor %}
            {% set min_viable_mtu = mtu_list | max %}
            network_config:
diff --git a/docs_user/modules/proc_adopting-networker-services-to-the-data-plane.adoc b/docs_user/modules/proc_adopting-networker-services-to-the-data-plane.adoc
index 8d7d1c160..f49af2a17 100644
--- a/docs_user/modules/proc_adopting-networker-services-to-the-data-plane.adoc
+++ b/docs_user/modules/proc_adopting-networker-services-to-the-data-plane.adoc
@@ -163,7 +163,7 @@ endif::[]
            ---
            {% set mtu_list = [ctlplane_mtu] %}
            {% for network in nodeset_networks %}
-           {{ mtu_list.append(lookup('vars', networks_lower[network] ~ '_mtu')) }}
+           {% set _ = mtu_list.append(lookup('vars', networks_lower[network] ~ '_mtu')) %}
            {%- endfor %}
            {% set min_viable_mtu = mtu_list | max %}
            network_config:
diff --git a/tests/roles/dataplane_adoption/defaults/main.yaml b/tests/roles/dataplane_adoption/defaults/main.yaml
index 7c74a41b4..fe8f15a87 100644
--- a/tests/roles/dataplane_adoption/defaults/main.yaml
+++ b/tests/roles/dataplane_adoption/defaults/main.yaml
@@ -121,7 +121,7 @@ edpm_network_config_template: |
   ---
   {% set mtu_list = [ctlplane_mtu] %}
   {% for network in nodeset_networks %}
-  {{ mtu_list.append(lookup('vars', networks_lower[network] ~ '_mtu')) }}
+  {%set _ = mtu_list.append(lookup('vars', networks_lower[network] ~ '_mtu')) %}
   {%- endfor %}
   {% set min_viable_mtu = mtu_list | max %}
   network_config:
diff --git a/tests/roles/dataplane_adoption/vars/ospdo.yaml b/tests/roles/dataplane_adoption/vars/ospdo.yaml
index 706676f1b..54d94029f 100644
--- a/tests/roles/dataplane_adoption/vars/ospdo.yaml
+++ b/tests/roles/dataplane_adoption/vars/ospdo.yaml
@@ -45,7 +45,7 @@ edpm_network_config_template: |
  ---
            {% set mtu_list = [ctlplane_mtu] %}
            {% for network in nodeset_networks %}
-           {{ mtu_list.append(lookup('vars', networks_lower[network] ~ '_mtu')) }}
+           {% set _ = mtu_list.append(lookup('vars', networks_lower[network] ~ '_mtu')) %}
            {%- endfor %}
            {% set min_viable_mtu = mtu_list | max %}
            network_config:
diff --git a/tests/roles/dataplane_adoption/vars/rhev.yaml b/tests/roles/dataplane_adoption/vars/rhev.yaml
index 84f9682c0..cc3bd697e 100644
--- a/tests/roles/dataplane_adoption/vars/rhev.yaml
+++ b/tests/roles/dataplane_adoption/vars/rhev.yaml
@@ -85,7 +85,7 @@ edpm_network_config_template: |
   ---
   {% set mtu_list = [ctlplane_mtu] %}
   {% for network in nodeset_networks %}
-  {{ mtu_list.append(lookup('vars', networks_lower[network] ~ '_mtu')) }}
+  {% set _ = mtu_list.append(lookup('vars', networks_lower[network] ~ '_mtu')) %}
   {%- endfor %}
   {% set min_viable_mtu = mtu_list | max %}
   network_config: