Activation email sends a wrong activationid

[auto]

vB 3.8
It seems that email confirmation email to activate sends out a wrong hash SOMETIMES. Some users are able to activate via email, but others get an incorrect activationid in the email.

For example, the useractivation table had this for activationid for a given user:
cfa17d3222cdcaa4edf96a56b6979558aed136b4

But his email that he forwarded over to me had this:
bd0c1bbc9e7204eb56f4e861b569bdba7341457a

I understand that some hacks for reason can affect this.
Anybody have a quick way to troubleshoot this?

Thanks!