JavaScript error on console

[mfranzke]

I am using Pattern Lab Node v5.15.5 on Mac, with Node v12.13.1, using a handlebars Edition with the demo patterns installed.

Expected Behavior

The pattern lab UI loads without any JavaScript errors on the browsers console.

Actual Behavior

The pattern lab UI loads with the following JavaScript error on the browsers console:

Uncaught (in promise) TypeError: s.a is not a constructor
    at Module.181 (pl-modal-viewer-chunk-a3ad014618a383c177cd.modern.js:formatted:92)
    at o (patternlab-viewer.modern.js:formatted:45)

Steps to Reproduce

Open https://patternlab-handlebars-preview.netlify.app/ in an evergreen browser and have a look at the developers bar console.