ff- chrome space-around bug

ff- chrome space-around different when single column/row

HTML

<div style="width:600px; height:100px">


  <div id="dtlist">
    <div class="b1   " style="width: 37%;">

      <div class="flex-cont " 
            style="height: 200px;">
        <div class="nkgs flex-item"> 22,50 </div>
        <div class="nkgs flex-item"> 12,60 </div>
        <div class="nkgs flex-item"> 22,85 </div>
        <div class="nkgs flex-item"> 12,50 </div>
        <div class="nkgs flex-item"> 22,50 </div>
        <div class="nkgs flex-item"> 23,50 </div>
        <div class="nkgs flex-item"> 26,90 </div>
        <div class="nkgs flex-item"> 23,50 </div>
        <div class="nkgs flex-item"> 12,50 </div>
        <div class="nkgs flex-item"> 22,50 </div>
        <div class="nkgs flex-item"> 225,00 </div>
        <div class="nkgs flex-item"> 12,50 </div>
        <div class="nkgs flex-item"> 23,50 </div>
        <div class="nkgs flex-item"> 12,60 </div>
      </div>

    </div>

    <div class="b1   " style="width: 37%;">

      <div class="flex-cont " style="height: 24%;">
        <div class="nkgs flex-item"> 22,60 </div>
        <div class="nkgs flex-item"> 12,50 </div>
      </div>

    </div>


  </div>




</div>

CSS

.flex-cont {
  display: flex;
  justify-content: flex-start;
  flex-flow: column wrap;
  align-content: space-around;
  align-content: space-evenly;
  align-items: flex-end;
}

.flex-item {
  /* display: inline-block; */
  flex: 0 1 auto;
  width: fit-content;
  border-bottom:1px dotted black;
}

.b1 {
  border: 1px solid black;
  --padding: 3px;
  -margin: 3px;
  display: inline-block;
  vertical-align: top;
  margin-left: 3px;
  margin-bottom: 6px;
}