Duplicated comment in customer notification when commenting on assignment

Summary

When commenting on an issue while assigning it to a user, the customer notification sent will contain the comment twice.

Steps to Reproduce

1. Create a Service Desk Issue via the portal
2. Ensure reporter is a customer
3. Using a service desk agent, assign issue to a service desk agent using assign button
4. Add a customer facing comment when performing the assignment
5. Check email account associated with the customer account for the notification

Expected Results

Customer notification should contain the comment only once, like any other customer facing comment:

Service Desk Agent commented:

Assigning this issue to an agent to investigate.

Actual Results

Customer notification contains the comment twice:

Service Desk Agent commented:

Assigning this issue to an agent to investigate.

---

Service Desk Agent commented:

Assigning this issue to an agent to investigate.

Workaround

Comment after doing the assignment so a normal customer notification is sent.