我不明白为什么我的具有height auto的div会占用其父级的全部高度

div.grid {
    display: flex;
    flex-wrap: wrap;
    width: 960px;
}

div.column {
    display: block;
    flex-basis: 37.5%;
    flex-grow: 0;
    flex-shrink: 0;
    /* height is actually set to auto, but it is computed like this */
    height: 132px;
}

<div class="grid">
    <div class="column">something</div>
    <div class="column">something<br>else<br>here</div>
    <div class="column">something</div>
</div>