UserAgent: Mozilla/5.0 (X11; CrOS x86_64 11151.61.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/71.0.3578.98 Safari/537.36
Platform: 11151.61.0 (Official Build) stable-channel eve

Example URL:
http://www.murderousmaths.co.uk/books/MMoE/4%20colour.htm

Steps to reproduce the problem:
1. Visit http://www.murderousmaths.co.uk/books/MMoE/4%20colour.htm
2. Right-click, select "Save as..." and save as single file .mhtml
3. Open the saved file in Chrome

What is the expected behavior?
The Web page is shown properly

What went wrong?
Chrome instead shows the source code (with the addition of a replacement character in every tag):

<�html><�head><�meta http-equiv="Content-Type" content="text/html; charset=UTF-16LE"> 
<�title>Murderous Maths of Everything: The Four Colour Map Theorem<�/title> <�style><�!-- 
a:hover{color:FF2222; }--><�/style>
...

Does it occur on multiple sites: N/A

Is it a problem with a plugin? No 

Did this work before? N/A 

Does this work in other browsers? N/A

Chrome version: 71.0.3578.98  Channel: stable
OS Version: 11151.61.0
Flash Version: 32.0.0.101

This may be due to the page being encoded in UTF-16?

Also,the saved mhtml file contains:

From: <Saved by Blink>
Snapshot-Content-Location: http://www.murderousmaths.co.uk/books/MMoE/4%20colour.htm
Subject: Murderous Maths of Everything: The Four Colour Map Theorem
Date: Tue, 15 Jan 2019 16:19:36 -0000
MIME-Version: 1.0
Content-Type: multipart/related;
  type="text/html";
  boundary="----MultipartBoundary--BPEfb7siu0s74JNbUwzffWthTGi2pqDl4NiAFTMoF8----"

------MultipartBoundary--BPEfb7siu0s74JNbUwzffWthTGi2pqDl4NiAFTMoF8----
Content-Type: text/html
Content-ID: <frame-E491F3728CCEB4D1462C8ABB46C61E03@mhtml.blink>
Content-Transfer-Encoding: quoted-printable
Content-Location: http://www.murderousmaths.co.uk/books/MMoE/4%20colour.htm

<=00h=00t=00m=00l=00>=00<=00h=00e=00a=00d=00>=00<=00m=00e=00t=00a=00 =00h=
=00t=00t=00p=00-=00e=00q=00u=00i=00v=00=3D=00"=00C=00o=00n=00t=00e=00n=00t=
=00-=00T=00y=00p=00e=00"=00 =00c=00o=00n=00t=00e=00n=00t=00=3D=00"=00t=00e=
=00x=00t=00/=00h=00t=00m=00l=00;=00 =00c=00h=00a=00r=00s=00e=00t=00=3D=00U=
...

If I remove all the "=00" it works.