Tracking URL changing automatically to a different one - google-schemas

Question

We have a Microdata Parcel Delivery markup code for our shipping confirmation email. Everything works great, but something strange happens.
For both the trackingUrl and the potentialAction url, we put our Narvar link: this is a service we use, that provides users with an intermediary page, where they see the status of their shipping and some additional info. If they want, on that page they can click on their UPS/FedEx/USPS link and go to their websites for more information.
In spite of this, when someone receives the email with the Markup code, right away the Narvar url is behind the button and call to action links. Then, after a few seconds, the button changes and the link "behind" it becomes the UPS/FedEx/USPS one.
The weird thing is that the UPS/FedEx/USPS link never appear in the Markup code, noyl the Narvar one does.
Has anyone experienced this and knows if this is expected?
Maybe the code automatically bypasses intermediary pages, recognizing the "final destination" and use that instead?
Can something be done to avoid this?
Thanks!
UPDATE: added code and screenshots
https://snag.gy/8ZBax6.jpg shows the email as soon as it hits the inbox: clicking in the link brings you to the Narvar web page
https://snag.gy/7tOD6l.jpg shows the email a few seconds after it got to the inbox: the link will bring you directly to the USPS website, no signs of Narvar
Here is the code we use:
<div itemscope itemtype="http://schema.org/ParcelDelivery">
<div itemprop="deliveryAddress" itemscope itemtype="http://schema.org/PostalAddress">
<meta itemprop="name" content="Stefano Pistillo"/>
<meta itemprop="streetAddress" content="63 Bovet Road Suite 224"/>
<meta itemprop="addressLocality" content="San Mateo"/>
<meta itemprop="addressRegion" content="CA"/>
<meta itemprop="addressCountry" content="US"/>
<meta itemprop="postalCode" content="94402"/>
</div>
<meta itemprop="expectedArrivalUntil" content="07/05/2018"/>
<div itemprop="carrier" itemscope itemtype="http://schema.org/Organization">
<meta itemprop="name" content="USPS PRIORITY MAIL NO CHARGE"/>
</div>
<div itemprop="itemShipped" itemscope itemtype="http://schema.org/Product">
<meta itemprop="name" content="W's Fitz Roy Down Jkt"/>
<link itemprop="url" href="http://www.patagonia.com/us/product/?p=84596-1-NVYB"/>
<link itemprop="image" href="http://www.patagonia.com/dis/dw/image/v2/ABBM_PRD/on/demandware.static/-/Sites-patagonia-master/default/images/hi-res/84596_NVYB.jpg?sw=100&sh=100&sm=fit&sfrm=png"/>
<meta itemprop="sku" content="84596"/>
<meta itemprop="color" content="NVYB"/>
</div>
<meta itemprop="trackingNumber" content="XXXXXXXXXX"/>
<link itemprop="trackingUrl" href="http://patagonia.narvar.com/patagonia/tracking/USPS?service=PP&ozip=94402&dzip=&tracking_numbers=XXXXXXXXXX"/>
<div itemprop="potentialAction" itemscope itemtype="http://schema.org/TrackAction">
<link itemprop="url" href="http://patagonia.narvar.com/patagonia/tracking/USPS?service=PP&ozip=94402&dzip=&tracking_numbers=XXXXXXXXXX"/>
</div>
<div itemprop="hasDeliveryMethod" itemscope itemtype="http://schema.org/ParcelService">
<meta itemprop="name" content="http://schema.org/ParcelService"/>
</div>
<div itemprop="partOfOrder" itemscope itemtype="http://schema.org/Order">
<meta itemprop="orderNumber" content="12345678"/>
<div itemprop="merchant" itemscope itemtype="http://schema.org/Organization">
<meta itemprop="name" content="Patagonia.com"/>
</div>
<link itemprop="orderStatus" href="http://schema.org/OrderInTransit"/>
</div>
</div>