Since the withRemove variable is a template flag, it can be undefined.
In the Entry\Card\_content.html.twig template for example, the withRemove variable is not defined.
{% for tag in tags %}
<li class="chip">
<a href="{{ path('tag_entries', {'slug': tag.slug}) }}">{{ tag.label }}</a>
- {% if withRemove %}
+ {% if withRemove is defined and withRemove == true %}
<a href="{{ path('remove_tag', { 'entry': entryId, 'tag': tag.id }) }}" onclick="return confirm('{{ 'entry.confirm.delete_tag'|trans|escape('js') }}')">
<i class="material-icons vertical-align-middle">delete</i>
</a>