this is happening for me as well, https is configured for the entire site, using .htaccess (i’ll use the above example.com values, rather than my actual website)
Steps to reproduce…
go to website: https://example.com
login, using sidebar login
page loads, indicating I’m logged in, I can click around the website and sidebar-login indicates i’m logged in
click on dashboard link: https://example.com/wp-admin
or profile link: https://example.com/wp-admin/profile.php
get redirected to https://example.com/wp-login.php?redirect_to=https%3A%2F%2Fexample.com%2Fwp-admin%2F&reauth=1
click on “← Back to example.com” homepage loads, i’m no longer logged in
or, if i go ahead and relogin it goes to https://example.com/wp-admin/ and i’m logged in
