I added that as well to enlarge the size of the icon needed, however, it’s still removing code – so it went from this:
<div class="wrap" style="text-align: center;"><a class="btn-11 ryv-popup" href="https://player.vimeo.com/video/140364516">
<span style="font-size:40px"><div class="ion-ios-videocam-outline"></div></span>
</a>
</div>
To this upon saving changes:
<div class="wrap" style="text-align: center;">
<a class="btn-11 ryv-popup" href="https://player.vimeo.com/video/140364516">
</a>
<div class="ion-ios-videocam-outline"></div>
</div>
In this case, the icon does show up, but only underneath the button instead of inside of it.