• I was not able to find an open or closed issue matching what I'm seeing

Setup

• Which version of Git for Windows are you using? Is it 32-bit or 64-bit?

$ git --version --build-options
git version 2.11.0.windows.1
sizeof-long: 4
machine: x86_64

I'm using a portable release: PortableGit-2.11.0-64-bit.7z.exe

• Which version of Windows are you running? Vista, 7, 8, 10? Is it 32-bit or 64-bit?

$ cmd.exe /c ver

Microsoft Windows [Version 6.1.7601]

Windows 7 Professional, Service Pack 1, 64-bit

• What options did you set as part of the installation? Or did you choose the
  defaults?

I have no install-options.txt file.

• Any other interesting things about your environment that might be related
  to the issue you're seeing?

I'm using diff-highlight.
I downloaded diff-highlight file from https://github.com/git/git/tree/master/contrib/diff-highlight and put it in %PathToPortableGit%\usr\bin\ directory.

.gitconfig

[core]
	autocrlf = false
	quotepath = false
[pager]
	log = diff-highlight | less
	show = diff-highlight | less
	diff = diff-highlight | less
[diff]
	compactionHeuristic = true

Details

• Which terminal/shell are you running Git from? e.g Bash/CMD/PowerShell/other

Bash

• What commands did you run to trigger this issue? If you can provide a
  Minimal, Complete, and Verifiable example
  this will help us understand the issue.

1. Build a test repository.

$ mkdir gitrepo
$ cd gitrepo
$ git init
$ touch test.txt

2. Rewrite test.txt as following, and save with BOM-less UTF-8 encoding.

+日本語のテキスト
+Write in Japanese
+

3. Add test.txt to the repository.

$ git add .
$ git commit -m "First commit"

4. Rewrite test.txt as following.

-日本語のテキスト
-Write in Japanese
+英語のテキスト
+Write in English

5. Now run git diff

$ git diff head

• What did you expect to occur after running these commands?

$ git diff head
diff --git a/test.txt b/test.txt
index 19ebe7c..e45d453 100644
--- a/test.txt
+++ b/test.txt
@@ -1,2 +1,2 @@
-日本語のテキスト
-Write in Japanese
+英語のテキスト
+Write in English

• What actually happened instead?

$ git diff head
diff --git a/test.txt b/test.txt
index 19ebe7c..e45d453 100644
--- a/test.txt
+++ b/test.txt
@@ -1,2 +1,2 @@
-<E6><97><A5><E6><9C><AC><E8><AA><9E><E3><81><AE><E3><83><86><E3><82><AD><E3><82><B9><E3><83><88>
-Write in Japanese
+<E8><8B><B1><E8><AA><9E><E3><81><AE><E3><83><86><E3><82><AD><E3><82><B9><E3><83><88>
+Write in English

Additional Notes

• It worked correctly when I used version 2.10.2.windows.1
• I did not change any config when updating to version 2.11.0.windows.1 from 2.10.2.windows.1