I can't see my purchase history after I changed the email address.

Was the purchase made as a guest or with a logged-in user?

KangSeungUk is my colleague.
Let me explain more.
It’s when a logged-in user buys.
A wordpress user can change his email and write another email in the ckeckout field.
In this case, multiple customer data will be inserted because of the different email.
But only one EDD_Customer instance is created to print the purchase history in the edd_get_users_purchases function.
This is critical and urgent in our project.
Please check it out.
Thanks in advance.

Is he changing the email while logged in from his profile page?

In my site, a logged-in user can both change his email at the profile page and write another email in the checkout field.
When he changes his email, he cannot see the previous purchase history. And when he write another email in checking out, he cant’t see the purchase item he bought just before.
I modified includes/user-functions.php and made a pull request.
Please check this out.
https://github.com/easydigitaldownloads/Easy-Digital-Downloads/pull/3619/files

I’ll check this problem with github.
https://github.com/easydigitaldownloads/Easy-Digital-Downloads/pull/3619