HTML Entities Characters In downloaded HTML

Hi, I sometime have to download the HTML file of an email built in Marketo to save it as OFT to send it to client. I noticed that every time I download the HTML file, every character disappear or display differently. I did some digging and noticed that even though I use HTML entities code for characters in the Marketo Email the downloaded code doesn't cary that code over. Every time I have to manually replace each missing character from the HTML code. Any idea how to prevent that?

Thank you in advance!