That should do it

client/components/cards/cardDetails.styl

@@ -81,9 +81,7 @@
       &.card-details-item-received,
       &.card-details-item-start,
       &.card-details-item-due,
-      &.card-details-item-end
-        width: 50%
-        flex-shrink: 1
+      &.card-details-item-end,
       &.card-details-item-customfield
         max-width: 50%
         flex-grow: 1