Multiple Timeline Notifications For Sent Estimates

Please see the attached screenshots. We are getting multiple sent notifications in the timeline when sending estimates.

The log shows that the email is actually being sent twice. So that we can investigate this further, please describe the steps that you are taking to send the estimate.

Is it possible that the "send" button is being clicked twice or that the page is being refreshed?
Has this always happened?
When did you first notice it?

The more detail that you provide the more likely we will be able to find the cause.

1. I create an estimate
2. I create a contract in another tab
3. I return to estimate tab refresh to show the new contract
4. Send the estimate to the customer
5. Then I exit the estimate tab
6. I am not refreshing the screen, as it does that automatically. I am not pressing twice.

First noticed this yesterday morning.