text-combine-horizontal, uppercase bug

by David Storey

HTML

<h1><span>z</span> 44 <span id="dig">82</span> 98</h1>

CSS

h1 {
    display: inline-block;
    font: bold 3.3em sans-serif;
    text-shadow: 2px 2px 0 black, 4px 4px 0 white;
    color: #ad2846;
    background-color: #d1d334;
    border: 5px solid #3d90a1;
    padding: .1em;
    -ms-writing-mode: tb-rl;
    -webkit-writing-mode: vertical-rl;
    -moz-writing-mode: vertical-rl;
    -ms-writing-mode: vertical-rl;
    writing-mode: vertical-rl;
    -webkit-text-orientation: upright;
    -moz-text-orientation: upright;
    -ms-text-orientation: upright;
    text-orientation: upright;
}
h1 span {
    -ms-text-combine-horizontal: all;
}
h1 span#dig {
     -ms-text-combine-horizontal: digits;
}