Setting ACCOUNT_EMAIL_VERIFICATION = 'optional' sets csrf cookie in response header - django

Question

I was taking a diff in the response header of wireshark traces of two applications and found that setting ACCOUNT_EMAIL_VERIFICATION = 'optional' in the settings.py changes the behaviour of the HTTP response cookie. It sets the csrf field in the cookie in the http header, which somehow fails my subsequent POST request as rest requests by giving me csrf validation failed error. Is this behaviour normal? Or am I supposed to do some other settings to change this. I am new to django.
Please go easy on me if it is something silly.
With ACCOUNT_EMAIL_VERIFICATION = 'optional'
Allow: POST, OPTIONS, HEAD\r\n
Vary: Accept, Cookie\r\n
Content-Type: application/json\r\n
X-Frame-Options: SAMEORIGIN\r\n
Set-Cookie: sessionid=5bp1r9cr167ice1kb8o1sjeo5i4yv05x; expires=Mon, 23-Mar-2015 18:52:12 GMT; httponly; Max-Age=1209600; Path=/\r\n
Set-Cookie: csrftoken=33tKW0NTfjdWZ4CNtpqK91BxEMniJECM; expires=Mon, 07-Mar-2016 18:52:12 GMT; Max-Age=31449600; Path=/\r\n
[truncated]Set-Cookie: messages="d113558d7ba4e1085f84fce405e0ad52e2d0442b$[[\"__json_message\"\0540\05425\054\"Successfully signed in as abhishek10.\"]\054[\"__json_message\"\0540\05425\054\"Successfully signed in as abhishek11.\"]\054[\
\r\n
With ACCOUNT_EMAIL_VERIFICATION = 'mandatory'
Allow: POST, OPTIONS, HEAD\r\n
Content-Type: application/json\r\n
X-Frame-Options: SAMEORIGIN\r\n
Vary: Accept, Cookie\r\n
Set-Cookie: sessionid=2k89iyebjvy4vqulqfiqntjaft2a2d68; expires=Mon, 23-Mar-2015 18:57:21 GMT; httponly; Max-Age=1209600; Path=/\r\n
\r\n