As you can see between the two boxes, I have added lines to structure the email correctly, however, upon sending an invoice to myself, this is what the email looks like in gmail:
Those spaces can be interpreted as “excess formatting” too, depending on your email application and preferences set by the recipient. This is out of Manager’s control. And as a general principle, it is not wise to try to create formatted content within the body of an email. With email, what you see is often not what you get.
I suspect you have Email sending format set to HTML. When rendering HTML, line breaks are ignored and consecutive white space is compressed to a single space character. To have the text formatted correctly when email formatting is set to HTML you can force line breaks either by inserting HTML line break tags or wrapping blocks of text in HTML paragraph tags
Alternatively, set Email sending format to Plain Text, and it should create the line breaks correctly.