fix

assets/sass/_theme/blocks/events.sass

 .block-agenda
+    &--grid,
+    &--large
+        .event
+            display: flex
+            flex-direction: column
+            position: relative
+            &-content
+                a 
+                    @include stretched-link
+            &-dates 
+                @extend .meta
+                margin-top: $spacing0
+                @include media-breakpoint-down(md)
+                    font-size: $h4-size
+                    line-height: $h4-line-height
+                    font-weight: $h4-weight
+        .media
+            order: -1
+            img
+                aspect-ratio: 1
+                object-fit: cover
+                margin-bottom: half($spacing0)
     &--grid .events
-        &:not(.unique)
-            @include grid(2, md)
-        &.unique .event
+        @include grid(2, md)
+        .event
+            @include media-breakpoint-down(desktop)
+                + .event 
+                    margin-top: $spacing1
+                &-dates
+                    text-align: right
+            &-content 
+                h2
+                    @extend .h3
+            &-description
+                margin-top: $spacing0
+    &--large
+        .event
             flex-direction: row
             grid-gap: $grid-gutter
-            .media
-                width: col(4, 8)
             &-content
                 flex: 1
                 .more
@@ -15,6 +46,8 @@
                     &::after
                         margin-left: half($spacing0)
             @include media-breakpoint-up(desktop)
+                .media
+                    width: col(4, 8)
                 &-dates
                     font-size: $h3-size-desktop
                     line-height: $h3-line-height
@@ -25,45 +58,21 @@
                     line-height: $h2-line-height
                     font-weight: $h2-weight
             @include media-breakpoint-down(desktop)
-                grid-gap: $grid-gutter-sm
+                flex-direction: column
+                grid-gap: 0
+                .media
+                    margin-left: calc(-#{$grid-gutter-sm} /2)
+                    margin-right: calc(-#{$grid-gutter-sm} /2)
+                    aspect-ratio: 1
                 .media:empty
                     display: none
-        .event
-            display: flex
-            flex-direction: column
-            position: relative
-            @include media-breakpoint-down(desktop)
-                + .event 
-                    margin-top: $spacing1
-            .media
-                order: -1
-                img
-                    aspect-ratio: 1
-                    object-fit: cover
-                    margin-bottom: half($spacing0)
-            &-dates 
-                @extend .meta
-                margin-top: $spacing0
-                @include media-breakpoint-down(md)
-                    font-size: $h4-size
-                    line-height: $h4-line-height
-                    font-weight: $h4-weight
-                    text-align: right
-            &-content 
-                a 
-                    @include stretched-link
-                h2
-                    @extend .h3
-            &-description
-                margin-top: $spacing0
 
-.block-agenda--grid 
+.block-agenda--large 
     @include in-page-with-sidebar
-        .events.unique .event .media:empty
+        .events .event .media:empty
             display: none
+
+.block-agenda--grid 
     @include in-page-without-sidebar
-        .events:not(.unique)
-            @include grid(3, desktop)
-            .unique
+        .events
+            @include grid(3, desktop)
\ No newline at end of file
-        .events.unique .event-content
-            position: relative
\ No newline at end of file

layouts/partials/blocks/templates/agenda.html

@@ -27,18 +27,14 @@
             {{ end -}}
           </div>
         {{ end -}}
-        {{ $rangeLength := len .events }}
-        {{ if eq $rangeLength 1 }}
-          {{ $isUnique = true }}
-        {{ end }}
-        <div class="events{{ if eq $rangeLength 1 }} unique{{ end}} ">
+        
+        <div class="events">
           {{ range .events }}
             {{ $event := site.GetPage .file }}
             {{ with $event }}
                 {{ partial "events/event" (dict 
                   "event" .
                    "layout" $layout
-                   "isUnique" $isUnique
                 ) }}
             {{ end }}
           {{ end }}

layouts/partials/events/event.html

 {{ $event := .event }}
 {{ $layout := "list" }}
 {{ $layout = .layout }}
-{{ $isUnique := .isUnique }}
 {{- $direction := "" -}}
 {{ $heading := .heading | default "h2" }}
 {{ $heading_tag := (dict 
@@ -25,8 +24,8 @@
       <a href="{{ .Permalink }}" title="{{ safeHTML (i18n "commons.more_aria" (dict "Title" $title)) }}" itemprop="name">{{ $title }}</a>
     {{ $heading_tag.close }}
 
-    {{ if eq $isUnique true }}
-      <div class="event-dates" itemprop="startDate" content="{{- if .Params.dates.from.day -}}{{ .Params.dates.from.day }}{{- end -}} {{- if .Params.dates.from.hour -}}{{ .Params.dates.from.hour }}{{- end -}}">
+    {{ if eq $layout "large" }}
+      <div class="event-dates meta" itemprop="startDate" content="{{- if .Params.dates.from.day -}}{{ .Params.dates.from.day }}{{- end -}} {{- if .Params.dates.from.hour -}}{{ .Params.dates.from.hour }}{{- end -}}">
         {{ .Params.dates.computed.short }}
         <div class="event-time">
           {{ if .Params.dates.from.hour }}
@@ -57,7 +56,7 @@
   {{ end }}
   </div>
 
-  {{ if eq $isUnique false }}
+  {{ if ne $layout "large" }}
     <div class="event-dates" itemprop="startDate" content="{{- if .Params.dates.from.day -}}{{ .Params.dates.from.day }}{{- end -}} {{- if .Params.dates.from.hour -}}{{ .Params.dates.from.hour }}{{- end -}}">
       {{ .Params.dates.computed.short }}
       <div class="event-time">