nosubject email being sent to our users

Hi guys

We have problem with the wp_email automatic . this only happens when we install another plugin for HTML emails / wp better emails or email templates . if only the wp_simple email is installed , it sends only the correct email and 1 email per operation as soon we install another plugin, it sends 2 emails per operation, one correct and one extra titled no subject and it comes from [email protected]

Beside the correct automated emails that an user should receive when making an operation on our website , they also receive an empty email from [email protected]
I was wondering why is this ? we have setup the automatic email to be from [email protected], everything is good, but they received this empty email along with the correct emails. the title is no subject and the email is empty

any idea how to solve this ?