I enabled 2FA using the Tether app.  I got an email for the verification, and I had to enter the code into the app as expected. 

However, for the web logins, https://www.tplinkcloud.com/ and this forum https://community.tp-link.com/, I can just login without the 2FA verification code.  I can also change the password on the account.

IMHO, this is terrible for security.  If 2FA is enabled, it should be enabled everywhere including the websites that take that account's credential.