SuiteCRM 7.5.1 Email Module: click "Reply" button, but got Related To: None

I was doing a activity report today, and noticed that, when I checked my emails, clicked on one of them, and clicked directly the blue button:" Reply", I was shown a window in the Email Module: Compose.

But the problem is, I tried to reply to a customer, say Bruce Lee, which is added into the SuiteCRM, but then I REPLY:

  • the “Related To” area is “NONE”,
  • “To” field is correct with the email address, but not showing the right way: it supposed to show like Mr. Bruce, but it’s showing

And, I got no new records listed in the Contact Module: History after I replied.

Anyone else’s facing this problem?