Yup, we all had this problem.
We are writing e-mails to several different people with same or similar content, only after we send it we see that portions of it are changed to purple.
Gmail does this as it regards copied text as quoted!
Easiest fix in the shortage of time is to COPY – PASTE THE CONTENT TO E-MAIL SUBJECT.
It will remove all formatting including the purple color of the text.
SELECT THE TEXT FROM THE SUBJECT AND COPY IT TO THE BODY.
Re-format it in couple of seconds and voila, you are sending normal e-mails.
I hope this was helpful.