{%
set eventUrl = urlFor(
    'event-detail', {"friendly_name": event.getUrlFriendlyName}
)
%}

<article class="cfp-event title-only">
    <h3 class="header">
        <a href="{{ eventUrl }}">{{ event.getName }}</a>
    </h3>
    <p class="meta">
        {{ event.getStartDate|date('M d Y', event.getFullTimezone) }}
        {%  if event.getStartDate|date('M d Y', event.getFullTimezone)
                is not sameas(event.getEndDate|date('M d Y', event.getFullTimezone)) %}
            &ndash; {{ event.getEndDate|date('M d Y', event.getFullTimezone) }}

        {% endif %}

        {% if event.getLocation %}
            @ {{event.getLocation|escape}}
        {% endif %}

        {% if event.getCallForPapersEndDate and event.getCallForPapersEndDate > "now"|date('c') %}
                {% if "now"|date('c') < event.getCallForPapersStartDate %}
                    {# not open yet #}
                    | Call for papers starts {{ event.getCallForPapersStartDate |date('M d Y', event.getFullTimezone) }}
                {% elseif "now"|date('c') < event.getCallForPapersEndDate %}
                    {# still open #}
                    | Call for papers ends {{ event.getCallForPapersEndDate |date('M d Y', event.getFullTimezone) }}
                {% endif %}
        {% endif %}
    </p>
</article>

{%
set eventUrl = urlFor(
    'event-detail', {"friendly_name": event.getUrlFriendlyName}
)
%}

<article class="cfp-event title-only">
    <h3 class="header">
        <a href="{{ eventUrl }}">{{ event.getName }}</a>
    </h3>
    <p class="meta">
        {{ event.getStartDate|date('M d Y', event.getFullTimezone) }}
        {%  if event.getStartDate|date('M d Y', event.getFullTimezone)
                is not sameas(event.getEndDate|date('M d Y', event.getFullTimezone)) %}
            &ndash; {{ event.getEndDate|date('M d Y', event.getFullTimezone) }}

        {% endif %}

        {% if event.getLocation %}
            @ {{event.getLocation|escape}}
        {% endif %}

        {% if event.getCallForPapersEndDate and event.getCallForPapersEndDate > "now"|date('c') %}
                {% if "now"|date('c') < event.getCallForPapersStartDate %}
                    {# not open yet #}
                    <br>Call for papers starts {{ event.getCallForPapersStartDate |date('M d Y', event.getFullTimezone) }}
                {% elseif "now"|date('c') < event.getCallForPapersEndDate %}
                    {# still open #}
                    <br>Call for papers ends {{ event.getCallForPapersEndDate |date('M d Y', event.getFullTimezone) }}
                {% endif %}
        {% endif %}
    </p>
</article>

Put CfP open and close date in summary onto separate lines.
Put CfP open and close date in summary onto separate lines.
