settings page non functional

Problem:
New install AT theme settings page not responding

What I'm using:

Dupal 8.3.6
Thunder distro
AT 8.x-2.0-dev
AT Tools 8.x-2.0-dev
online hosted site

Created an AT subtheme
used adminimal admin theme
This is a fresh install of 1 day.
All was working well until the main admin stopped working
fixed with by switching back to a bartik admin subtheme

Going to the subtheme settings page on firefox the script gets hung (repeated after cache cleared and DB update)
Switched to chrome. The script does not hang (but runs sloooow) but no changes to the setting page are accepted.

Could this be a preprocessor problem? A theme bug? A browser issue?

Thoughts??

This is the debug error on firefox if it helps....
/*! jQuery v2.2.4 | (c) jQuery Foundation | jquery.org/license */
!function(a,b){"object"==typeof module&&"object"==typeof module.exports?module.exports=a.document?b(a,!0):function(a){if(!a.document)throw new Error("jQuery requires a window with a document");return b(a)}:b(a)}("undefined"!=typeof window?window:this,function(a,b){var c=[],d=a.document,e=c.slice,f=c.concat,g=c.push,h=c.indexOf,i={},j=i.toString,k=i.hasOwnProperty,l={},m="2.2.4",n=function(a,b){return new n.fn.init(a,b)},o=/^[\s\uFEFF\xA0]+|[\s\uFEFF\xA0]+$/g,p=/^-ms-/,q=/-([\da-z])/gi,r=function(a,b){return b.toUpperCase()};n.fn=n.prototype={jquery:m,constructor:n,selector:"",length:0,toArray:function(){return .... and it continues on and on..