Dmx-bind isn't working for this counter.js script

I’m using this script:
https://codepen.io/syedrafeeq/pen/rcfsJ

and have the numbers counting up perfectly when it’s static values. I thought it would be a simple case of changing it to use dmx-bind but that just gives me a zero.

Static code:
<h1 class="timer count-title count-number" data-to="2000" data-speed="1500">2000</h1>

Attempted dynamic code:
<h1 class="timer count-title count-number" dmx-bind:data-to="{{connStats.data.queryTotalMembers[0].totalMembers}}" data-speed="1500"></h1>

It should work, shouldn’t it? The variable {{connStats.data.queryTotalMembers[0].totalMembers}} is giving me the correct number if I just display it normally.