Extract from an email header the Authentication-Results part using an Outlook Add-in with OfficeJS

Question

I've been trying to the section of Authentication-Results First I tried with:

Office.context.mailbox.item.internetHeaders.getAsync

But for some reason interneHeader keeps returning undefined so I move to:

Office.context.mailbox.item.getAllInternetHeadersAsync

In my tests with Regex on it I got results from the first line of it.

But when I use it on copying email headers on regex101 or Node I got the information I need. Meaning the entire section with spf, dkim and dmarc.

I use this regex:

header.match(/^Authentication-Results:[0-9a-zA-Z =\(\)\.\n;-]*$/gm)[0]

Exemple: This is a sample of header from a Steam email:

Received: from SN1NAM02FT0054.eop-nam02.prod.protection.outlook.com
 (2603:10b6:806:127:cafe::f5) by SN7PR04CA0211.outlook.office365.com
 (2603:10b6:806:127::6) with Microsoft SMTP Server (version=TLS1_2,
 cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4930.15 via Frontend
 Transport; Tue, 1 Feb 2022 20:13:03 +0000
Authentication-Results: spf=pass (sender IP is xxx.xxx.xxx.xxx)
 smtp.mailfrom=steampowered.com; dkim=pass (signature was verified)
 header.d=steampowered.com;dmarc=pass action=none
 header.from=steampowered.com;compauth=pass reason=100
Received-SPF: Pass (protection.outlook.com: domain of steampowered.com
 designates xxx.xxx.xxx.xxx as permitted sender)
 receiver=protection.outlook.com; client-ip=xxx.xxx.xxx.xxx;
 helo=smtp-03-tuk1.steampowered.com;

Using the my regex, on it it returns this:

Authentication-Results: spf=pass (sender IP is xxx.xxx.xxx.xxx)
 smtp.mailfrom=steampowered.com; dkim=pass (signature was verified)
 header.d=steampowered.com;dmarc=pass action=none
 header.from=steampowered.com;compauth=pass reason=100

But when I use with Office.context.mailbox.item.getAllInternetHeadersAsync It only returns this:

Authentication-Results: spf=pass (sender IP is xxx.xxx.xxx.xxx)

So I wanna what approach I can do to this issue?