Hello,

Thanks for pointing this out. Our tests didn't show it originally due to CSS Caching on our test servers. The issue lies within the Joomla! isis tempalate/js/template.js this has been changed and now doesn't allow more than 1 btn-group option to be selected.

In the interim you can revert the Joomla! .js file back to the V3.8.11, since it was only strict standard/typo updates.

We will work on a fix around this for a release this week.

Many thanks
Tony