Programming

I don't believe it. Let me compare myself;)
Unless it's these points:

After that, it was opened in a text editor, and a 32-character text string was added to the beginning (including the newline character before the exe file content, making it 33 characters).

A text editor is a poorly controlled tool. It can add even more characters at its discretion. For example, an end-of-file character at the very end of the file. Also, you say that you added 33 characters (because a newline is also a character). But you only remove 32 (leaving the 33rd). So, the error might be in that.
But I don't believe that after all the operations, you got exactly the same test.exe that you had before. No way.