TortoiseGitMerge Redo is not recorded as change

What steps will reproduce the problem?

1. Create a new local Git repository
2. Commit a file test.txt with content test (commit message does not matter)
3. Change the content of test.txt to test1
4. Open the Git Commit dialog
5. Double click the modified test.txt file
6. Select "Double pane view"
7. In the "Working Tree" pane change the content back to test
   ℹ The file name has now a * indicating a change
8. Press the "Undo" button
   ℹ The * is removed from the file name
9. Press the "Redo" button
   ❌ The file content is now test, which differs from the original test1, but the file name has no * and is not marked as changed, e.g. you can close the TortoiseGitMerge window without a warning about unsaved changes

What is the expected output? What do you see instead?

Redo-ing a change which has not been saved should mark the file as modified, that is:

• A * should be shown in front of the file name
• When closing the TortoiseGitMerge window you should be warned about unsaved changes

What version of TortoiseGit and Git are you using? On what operating system?

TortoiseGit 2.12.0.0 git version 2.33.0.windows.1

Windows 10

Please provide any additional information below.