Static Emails Not Imported

Do you have multiple Email Address fields? If so, it'd be worth checking if you've selected the correct Email Address field in the list import dialog, sometimes, the dialog makes it difficult to read the complete field name, and you'd need to scroll to the right to verify if the correct field is selected or not.

Also, while importing, did you see any squiggly lines underneath the field(s)? The red squiggly line indicates that multiple columns of the list import file are mapped with a single Marketo field, and the green indicates that the field updates are blocked on the selected field. Lastly, I'd also check if the email address values in the import file are properly added.