Null Result for ReceivedDate Property in MailMessage

I'm using Rebex to create a MailMessage object from the stream of an email obtained through Graph. The response of the call shows the receivedDateTime property properly populated, but when I use the following code:

MailMessage mailMessage = new MailMessage();
mailMessage.Load(stream);

The mailMessage.ReceivedDate property turns out to be null. Does anyone have any ideas on how to resolve this issue or has encountered a similar situation before? Thanks in advance for the help!