I've added the following to my template.js to fix it, temporarily.

// Ugly hack to force sliders to fire the underlying input's keyup event so in-group expressions are properly updated.
$( document ).ready( function() {
// use both slider-container (latest build) and withslider (current build - 160317).
// TODO: At each LS update, check if issue 11072 has been resolved. If so, remove this hack.
$("div.slider-container input, div.withslider input").change( function() { $(this).keyup() } );
})

We don't trigger keyup in current version. That might be the problem.

yep

Fix committed to master branch: http://bugs.limesurvey.org/plugin.php?page=Source/view&id=18813

Should be fixed. Can you pull and check if it works for you?

I quickly did a drop-in replace of the affected file, seems to have done the trick, thanks!

Version 2.50+ Build 160430 released