SendGrid INC on "[Plugin: SendGrid] 10 time duplicate email sending after plugin update"

Hello,
I'm sending email via sendgrid plugin to my subscribers. I've some issues from 2 day, it started on monday.
How can I avoid this problem?
Thank you
Jessica

https://wordpress.org/plugins/sendgrid-email-delivery-simplified/

Hi Jessica,

Can you provide us more details on how to reproduce this issue?
How and where do you call the wp_mail() function?

Thank you,
SendGrid

I'm using this plugin to send new post notification via sendgrid:

Better Notifications for WordPress
Link

I have tried to reproduce the issue with 'Better Notifications for WordPress' plugin but I couldn`t manage to do it.
Please check your e-mail activity in your SendGrid account and see if there is something wrong.
Also, please provide us more info:
1. What send method do you use ? (API or SMTP)
2. What authentication method do you use ? (APIKey or Credentials)
3. Other details that you think might be useful for us.

Thank you,
SendGrid

Send method: API

I can see that saving new articles takes many time but this thing I don't know if is important or not to resolve this issue.
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Send method: API
Authentication method: Credentials
sendgrid version: 1.7.3
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wordpress version: 4.4.2
better notification for wordpress version: 1.3.9.4
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I can't reproduce the issue.
We think it is caused by your hosting added with the plugin (better notification for wordpress) .
Can you please try to send a test e-mail from the SendGrid's plugin seetings page to see if you can reproduce the issue?