Cannot fetch internet headers for an email item when replying/forwarding from the "Sent" folder of a user

We have an Office.js add-in running in Exchange Server. When a user sends an email using our add-in, we add an internet header to the email item.

When a user then tries to reply to/forward that email, our add-in tries to fetch the internet header set previously. This fetched value is then used further for processing the email.

The issue is that if the user tries to reply to/forward an email from the "Sent" folder, then we are not able to fetch any internet headers for the parent mail. We can fetch the internet headers for the parent mail when replying/forwarding from the user's inbox.

We are using the following EWS API to fetch the internet header:

We have faced this issue on browsers (Google Chrome, MS Edge, Safari, and Mozilla Firefox) as well as on Outlook on Mac (classic UI).

Any information around this, insights into the issue, or possible workarounds for this issue will be greatly appreciated.

Thanks