The Email criteria in the HubSpot Lists tool evaluates contacts based on all historical email activity, like clicks, for all email addresses ever associated with a contact record from the time that email address is associated with the contact. Even if the email address of the contact is later changed, the interactions from their previous email address are still counted towards list segmentation.
For example, a contact submits a form with his or her personal email address (firstname.lastname@example.org) and you send them an email titled "Thank you for subscribing!". Later, they submit a form again with their business email address (email@example.com). HubSpot deduplicates the contact using cookies and updates the contact's email property with this new address (firstname.lastname@example.org). You then create a list and want to include all contacts who received the "Thank you for subscribing!" email. The contact will meet the criteria for the list, even though they received the email at email@example.com and the email address currently set on their record is firstname.lastname@example.org.