Concerning: this app can break
Yup, you’re right, Notepad saves it in ANSI, but then opens it up as Unicode by default. So Notepad’s rules for testing a file’s encoding aren’t perfect yet.
To see the correct content, all one has to do is force Notepad to open the file with ANSI encoding… File/Open/(don’t select a file)/(change encoding to ANSI)… Notepad isn’t broken, it just isn’t parsing it right.
Did the source explain what it is about those four words that beat the application’s logic? I’ve never seen this happen with any other content.