I have spent the better part of a day looking at this issue. As roedel stated, it DOES have to do with the dollar sign ($). the way this contribution works, when including dollar amounts in the email, it is interpreting it as a variable;
For example: if you had a value to include in the email of "$12,567.89", the "$12" would be interpreted as a null value variable and the ",567.89" would display in the email text.
The easy fix is to replace the "$" with "\$" before including the text in the email: