Having weird issues trying to store an HTML file with the temporaryBlobStorage inferace

I’m having strange errors with a formula I’m trying to create. The API I’m working with returns HTML in a json response that looks like this:

{
    "templateId": 1463638,
    "metadata": {
        "templateId": 1463638,
        "createdAt": 1582490255641,
        "updatedAt": 1648063682857,
        "name": "SNIPPET/TOKEN TESTING - Catalog 02/20",
        "creatorUserId": "test@email.com",
        "messageTypeId": 19854
    },
    "name": "SNIPPET/TOKEN TESTING - Catalog 02/20",
    "fromName": "Davida Gaffney",
    "fromEmail": "test@email.com",
    "subject": "I'm testing tokens using snippets",
    "preheaderText": "",
    "ccEmails": [
        "{{ccEmails}}"
    ],
    "bccEmails": [],
    "html": "<!DOCTYPE html PUBLIC \"-//W3C//DTD XHTML 1.0 Transitional//EN\" \"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd\">\n<html lang=\"en\" style=\"background-color:#f3f3f3\" xml:lang=\"en\" xmlns=\"http://www.w3.org/1999/xhtml\">\n<head>\n\t<link href=\"https://fonts.googleapis.com/css?family=Crimson+Text:400,600\" rel=\"stylesheet\" />\n\t<link href=\"https://fonts.googleapis.com/css?family=Cormorant+Garamond:300,600\" rel=\"stylesheet\" /><meta http-equiv=\"Content-Type\" content=\"text/html; charset=utf-8\"><meta name=\"viewport\" content=\"width=device-width\">\n\t<title>StorageMart</title>\n\t<!-- Outlook Conditional --><!--[if mso]>\n<style type=\"text/css\">\nbody, table, td {font-family: 'OpenSans', sans-serif !important;}}\na {\ncolor: inherit !important;\ntext-decoration: underline !important;\n}}\n</style>\n<![endif]--><!--[if (gte mso 9)|(IE)]>\n<style>\ntable.body .columns.padding-none {\npadding-left: 0 !important;\npadding-right: 0 !important;\npadding-top: 0 !important;\npadding-bottom: 0 !important;\n}}\ntable.body .columns.padding-left-none {\npadding-left: 0 !important;\n}}\ntable.body .columns.padding-right-none {\npadding-right: 0 !important;\n}}\ntable.body .columns.padding-top-none {\npadding-top: 0 !important;\n}}\ntable.body .columns.padding-bottom-none {\npadding-bottom: 0 !important;\n}}\n.margin-bottom-none,\np  .margin-bottom-none {\nmargin-bottom: 0 !important;\n}}\np.text-right {\ntext-align: right !important;\n}}\n</style>\n<![endif]--><!--[if mso]>\n<style>\ntable.body .columns.padding-none {\npadding-left: 0 !important;\npadding-right: 0 !important;\npadding-top: 0 !important;\npadding-bottom: 0 !important;\n}}\ntable.body .columns.padding-left-none {\npadding-left: 0 !important;\n}}\ntable.body .columns.padding-right-none {\npadding-right: 0 !important;\n}}\ntable.body .columns.padding-top-none {\npadding-top: 0 !important;\n}}\ntable.body .columns.padding-bottom-none {\npadding-bottom: 0 !important;\n}}\n.margin-bottom-none,\np  .margin-bottom-none {\nmargin-bottom: 0 !important;\n}}\np.text-right {\ntext-align: right !important;\n}}\n</style>\n<![endif]--><!-- Styling for apple links -->\n\t<style type=\"text/css\">@media only screen{\n      html{\n        min-height:100%;\n        background:#f3f3f3}\n      }\n      }\n      }\n      @media only screen and (max-width:616px){\n        .small-float-center{\n          margin:0 auto!important;\n          float:none!important;\n          text-align:center!important}\n      }\n      .small-text-center{\n        text-align:center!important}\n      }\n      }\n      }\n      @media only screen and (max-width:616px){\n        .hide-for-large{\n          display:block!important;\n          width:auto!important;\n          overflow:visible!important;\n          max-height:none!important;\n          font-size:inherit!important;\n          line-height:inherit!important}\n      }\n      }\n      }\n      @media only screen and (max-width:616px){\n        table.body table.container .hide-for-large,table.body table.container .row.hide-for-large{\n          display:table!important;\n          width:100%!important}\n      }\n      }\n      }\n      @media only screen and (max-width:616px){\n        table.body img{\n          width:auto;\n          height:auto}\n      }\n      table.body center{\n        min-width:0!important}\n      }\n      table.body .container{\n        width:95%!important}\n      }\n      table.body .columns{\n        height:auto!important;\n        -moz-box-sizing:border-box;\n        -webkit-box-sizing:border-box;\n        box-sizing:border-box;\n        padding-left:16px!important;\n        padding-right:16px!important}\n      }\n      table.body .columns .columns{\n        padding-left:0!important;\n        padding-right:0!important}\n      }\n      th.small-1{\n        display:inline-block!important;\n        width:8.33333%!important}\n      }\n      th.small-5{\n        display:inline-block!important;\n        width:41.66667%!important}\n      }\n      th.small-6{\n        display:inline-block!important;\n        width:50%!important}\n      }\n      th.small-7{\n        display:inline-block!important;\n        width:58.33333%!important}\n      }\n      th.small-10{\n        display:inline-block!important;\n        width:83.33333%!important}\n      }\n      th.small-12{\n        display:inline-block!important;\n        width:100%!important}\n      }\n      table.menu{\n        width:100%!important}\n      }\n      table.menu td,table.menu th{\n        width:auto!important;\n        display:inline-block!important}\n      }\n      }\n      }\n      @media screen and (max-width:596px){\n        .partial.testimonial .testimonial-content .columns.small-1{\n          display:none!important}\n      }\n      .partial.testimonial .testimonial-content .columns.small-10{\n        width:100%!important}\n      }\n      }\n      }\n      @media screen and (max-width:616px){\n        .partial.social-media-icons .menu-item{\n          padding-right:10px}\n      }\n      .partial.social-media-icons .menu-item:last-child{\n        padding-right:0}\n      }\n      }\n      }\n\t</style>\n</head>\n<body style=\"-moz-box-sizing:border-box;-ms-text-size-adjust:100%;-webkit-box-sizing:border-box;-webkit-text-size-adjust:100%;Margin:0;background-color:#f3f3f3;box-sizing:border-box;color:#333;font-family:Arial,sans-serif;font-size:16px;font-weight:400;line-height:1.3;margin:0;min-width:100%;padding:0;text-align:left;width:100%!important\">\n<div style=\"padding: 20px\">\n<h2>STORE DETAILS</h2>\n\n<div style=\"border-bottom: 1px solid black; padding-bottom: 20px;\">\n<h3><b>Moved Coupon</b></h3>\n<br />\n<span style=\"color:#2ecc71;\">&nbsp; &nbsp;catalog: {{{ snippet \"Moved Coupon Logic\" }}}</span></div>\n\n<div style=\"border-bottom: 1px solid black; padding-bottom: 20px;\">\n<h3></h3>\n</div>\n</div>\n</body>\n</html>\n",
    "plainText": "",
    "dataFeedIds": [],
    "cacheDataFeed": true,
    "mergeDataFeedContext": false,
    "messageTypeId": 19854,
    "creatorUserId": "davida.gaffney@storage-mart.com"
}

I’ve been trying to work on a way to get the “html” string to be displayed in Coda. I can’t return it with the ValueHintType as Html since it uses unsupported tags, so I’ve been looking into turning it into a buffer, storing it with temporaryBlobStorage and returning it with the ValueHintType as attachment. I’ve written this to accomplish that:

pack.addFormula({
	name: "GetTemplateHTML",
	description: "Get raw html of a template from Iterable.",
	parameters: [
		coda.makeParameter({
			type: coda.ParameterType.Number,
			name: "templateId",
			description: "Template's ID in Iterable.",
		}),
	],
	resultType: coda.ValueType.String,
	codaType: coda.ValueHintType.Attachment,
	execute: async function ([templateId], context) {
		let response = await context.fetcher.fetch({
				method: "GET",
				url: coda.withQueryParams("https://api.iterable.com/api/templates/email/get", {
					templateId: templateId,
				}),
			}),
			data = Buffer.from(response.body.html, "utf-8");

		return await context.temporaryBlobStorage.storeBlob(data, "text/html;charset=UTF-8");
	},
});

The pack builds correctly and uploads just fine with this code, but whenever I try to execute the formula in my doc I get this error:

User ID 1053924
Connection ID 28286d11-85c1-4117-923b-4255deddc32d
Pack Version 98
Pack ID 11030
Request ID 91f5443b-8cc8-4f62-9a58-73e77e04346a
Created at Apr 6, 2022 @ 09:19:52
Request type invokeFormulaRequest
Duration 2063ms
Error 13 INTERNAL: Request message serialization failure: Failure: Cannot coerce to Uint8Array: object
Stack trace: at processTicksAndRejections (internal/process/task_queues.js:77:11) 

I’ve tried to change the encoding away from utf-8 however that did not work. I’m really not sure what’s going on here since I’ve read that a Buffer instance is also an instace of a Uint8Array. What would you reccomend I change with my code, or is this implementation of temporaryBlobStorage not supported?