Dynamics 365 Email Bug - While Using Legacy Forms

While working with Emails, when legacy form rendering is enabled, I found one bug in Dynamics 365 which makes the "From" field blank and locks the "Regarding" field as soon as email changes are saved on "Received" emails. This bug can be reproduced using the following steps:

Let's say we have one queue configured. Our sales team sent one email to this queue. You can see in the following email, under the "From" field the sales team address is there but the "Regarding" field is blank.

Now, I have created one contact with our sales team email address and I want to set "Regarding" to that contact. So, I look for this email address and after setting the "Regarding" field, as soon as I save the email form, it locks the "Regarding" field and makes the "From" field blank like the following.


As a workaround, we need to reload the email form to bring Form field values back.

Hope it will help someone !!