Newly created Portal interface serving blank screen

Describe the bug Using a common demo scenario, visiting a newly created Portal shows a blank screen, although there is content being served. There are no errors I could find in the logs. The various portal resources (Environment, Portal, etc) do not show errors. I can reproduce this, including starting from scratch.

To Reproduce

Install Edge Enterprise 1.9.1 and Portal 1.1.1. I'm doing all this on GKE.
Set up /etc/hosts for api.example.com and petstore.example.com on a local workstation to point to GKE external IP address.
kubectl apply -f https://raw.githubusercontent.com/jameshbarton/solo-resources/main/argo-petstore/library/1-apidoc.yaml
kubectl apply -f https://raw.githubusercontent.com/jameshbarton/solo-resources/main/argo-petstore/library/2-apiprod.yaml
kubectl apply -f https://raw.githubusercontent.com/jameshbarton/solo-resources/main/argo-petstore/library/3-envt.yaml

API access should work as expected:

% curl http://api.example.com/api/pets -i
HTTP/1.1 200 OK
content-type: application/xml
date: Tue, 16 Nov 2021 21:13:52 GMT
content-length: 86
x-envoy-upstream-service-time: 2
server: envoy

kubectl apply -f https://raw.githubusercontent.com/jameshbarton/solo-resources/main/argo-petstore/library/4-group-user-passwd.yaml
kubectl apply -f https://raw.githubusercontent.com/jameshbarton/solo-resources/main/argo-petstore/library/5-portal.yaml
curling the api.example.com endpoint should still work as expected.
Visit http://petstore.example.com from browser. I used Chrome both in standard and incognito mode with same results, also Safari and Firefox. There are no errors in logs or Portal CRs or generated VS or RT. Everything is also green in the portal admin console.

Observe a blank screen. Doing a view source shows the following content:

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8"/>
  <link rel="icon" id="favicon" href="default-favicon.png"/>
  <meta name="viewport" content="width=device-width,initial-scale=1"/>
  <meta name="theme-color" content="#000000"/>
  <meta name="description" content="A portal for your Gloo'd together APIs"/>
  <link rel="apple-touch-icon" href="/logo192.png"/>
  <link rel="manifest" href="/manifest.json"/>
  <title id="page-title">Solo.io Gloo Portal</title>
  <link href="/static/css/2.a1951d86.chunk.css" rel="stylesheet">
  <link href="/static/css/main.9f4fffb6.chunk.css" rel="stylesheet">
</head>
<body>
  <noscript>You need to enable JavaScript to run this app.</noscript>
  <div id="root"></div>
  <script>!function(e){function r(r){for(var n,i,l=r[0],f=r[1],a=r[2],c=0,s=[];c<l.length;c++)i=l[c],Object.prototype.hasOwnProperty.call(o,i)&&o[i]&&s.push(o[i][0]),o[i]=0;for(n in f)Object.prototype.hasOwnProperty.call(f,n)&&(e[n]=f[n]);for(p&&p(r);s.length;)s.shift()();return u.push.apply(u,a||[]),t()}function t(){for(var e,r=0;r<u.length;r++){for(var t=u[r],n=!0,l=1;l<t.length;l++){var f=t[l];0!==o[f]&&(n=!1)}n&&(u.splice(r--,1),e=i(i.s=t[0]))}return e}var n={},o={1:0},u=[];function i(r){if(n[r])return n[r].exports;var t=n[r]={i:r,l:!1,exports:{}};return e[r].call(t.exports,t,t.exports,i),t.l=!0,t.exports}i.m=e,i.c=n,i.d=function(e,r,t){i.o(e,r)||Object.defineProperty(e,r,{enumerable:!0,get:t})},i.r=function(e){"undefined"!=typeof Symbol&&Symbol.toStringTag&&Object.defineProperty(e,Symbol.toStringTag,{value:"Module"}),Object.defineProperty(e,"__esModule",{value:!0})},i.t=function(e,r){if(1&r&&(e=i(e)),8&r)return e;if(4&r&&"object"==typeof e&&e&&e.__esModule)return e;var t=Object.create(null);if(i.r(t),Object.defineProperty(t,"default",{enumerable:!0,value:e}),2&r&&"string"!=typeof e)for(var n in e)i.d(t,n,function(r){return e[r]}.bind(null,n));return t},i.n=function(e){var r=e&&e.__esModule?function(){return e.default}:function(){return e};return i.d(r,"a",r),r},i.o=function(e,r){return Object.prototype.hasOwnProperty.call(e,r)},i.p="/";var l=this.webpackJsonpui=this.webpackJsonpui||[],f=l.push.bind(l);l.push=r,l=l.slice();for(var a=0;a<l.length;a++)r(l[a]);var p=f;t()}([])</script><script src="/static/js/2.71cc5e45.chunk.js"></script><script src="/static/js/main.0871e48e.chunk.js"></script>
</body>
</html>

I do see these http 500 errors in Chrome Dev Tools.

Expected behavior Portal should display as expected.

Additional context

Gloo Portal version 1.1.1
Kubernetes version v1.20.10-gke.1600
Gateway technology and version: Gloo Edge Enterprise v1.9.1

solo-io / gloo-portal-issues

Newly created Portal interface serving blank screen #132