Issue with eXist and simple embedding

[MedievalMatt]

I'm attempting to use the simple embedded javascript version of Mirador, called via unpkg, within an eXist application. The code works fine as straight HTML, but within eXist it initially instantiates but I get the following error if I attempt to interact with the canvas at all:

index.js:209 RangeError: Maximum call stack size exceeded
    at c (getScrollParent.js:27:31)
    at G (setupEventListeners.js:11:7)
    at G (mirador.min.js:2:1038206)
    at G (mirador.min.js:2:1038206)
    at G (mirador.min.js:2:1038206)
    at G (mirador.min.js:2:1038206)
    at G (mirador.min.js:2:1038206)
    at G (mirador.min.js:2:1038206)
    at G (mirador.min.js:2:1038206)
    at G (mirador.min.js:2:1038206)
os @ index.js:209
n.callback @ index.js:226
mi @ index.js:131
us @ index.js:212
Oc @ index.js:255
t.unstable_runWithPriority @ factoryWithThrowingShims.js:19
qo @ index.js:122
wc @ index.js:248
sc @ index.js:239
(anonymous) @ index.js:123
t.unstable_runWithPriority @ factoryWithThrowingShims.js:19
qo @ index.js:122
Xo @ index.js:123
Yo @ index.js:122
nc @ index.js:230
ya @ index.js:163
(anonymous) @ useControlled.js:38
we @ MenuItem.js:273
(anonymous) @ MenuItem.js:306
setTimeout (async)
(anonymous) @ MenuItem.js:305
s @ index.js:14
p @ index.js:14
(anonymous) @ index.js:14
v @ index.js:15
st @ index.js:52
it @ index.js:51
ct @ index.js:52
ht @ index.js:56
L @ index.js:287
F @ index.js:19
Jt @ index.js:70
Qt @ index.js:69
t.unstable_runWithPriority @ factoryWithThrowingShims.js:19
Xt @ index.js:68
getScrollParent.js:27 Uncaught RangeError: Maximum call stack size exceeded
    at c (getScrollParent.js:27:31)
    at G (setupEventListeners.js:11:7)
    at G (mirador.min.js:2:1038206)
    at G (mirador.min.js:2:1038206)
    at G (mirador.min.js:2:1038206)
    at G (mirador.min.js:2:1038206)
    at G (mirador.min.js:2:1038206)
    at G (mirador.min.js:2:1038206)
    at G (mirador.min.js:2:1038206)
    at G (mirador.min.js:2:1038206)

This is using the Harvard manifest provided in the examples and following how the html is structured there. It's about as simple as the html code can get within eXist:

   <script src="https://unpkg.com/mirador@latest/dist/mirador.min.js"/>
   <div id="mirador"/>
   <script type="text/javascript">
      const mirador = Mirador.viewer({
  "id": "mirador",
    "manifests": {
    "https://iiif.lib.harvard.edu/manifests/drs:48309543": {
      "provider": "Harvard University"
    }
  },
  "windows": [
    {
      "loadedManifest": "https://iiif.lib.harvard.edu/manifests/drs:48309543",
      "canvasIndex": 2,
      "thumbnailNavigationPosition": 'far-bottom'
    }
  ]
});
    </script>

The issue seems to be with react-dom.production.min.js from within the Webpack created for the unpkg site. Is there different way I should be approaching integration with the eXist site? If not, why are the multiple calls being generated to the point that it errors out and hangs my browser?