Some Sender's Email Address Have An Extra 3 Hexadecimal Digits

Question

I have an application using Outlook PIA reading from a client's Exchange server for some years. Lately, where a MailItem's SenderEmailType is "EX", the SenderEmailAddress has three of what looks like hexadecimal characters at the end. An example:

/O=xxxx/OU=EXCHANGE ADMINISTRATIVE GROUP (FYDIBOHF23SPDLT)/CN=RECIPIENTS/CN=nnn nnn nnnD02

I don't know how the company run their Exchange. But it seems that this happens only for recently added employees.

What could be the cause of the three extra characters and how can I handle or work around them?

Answer 1

Why is it important? It what it is, the display name and the SMTP addresses are not affected. For all practical purposes, EX type addresses must be treated as black boxes.