This is a speciality of some Windows sorting algorithms, which employ something called word sort technique.
In this type of sort, all punctuation marks and other non-alphanumeric characters, except for the hyphen and the apostrophe, come before any alphanumeric character. The hyphen and the apostrophe are treated differently from the other non-alphanumeric characters to ensure that words such as "Boi-Ngo" and "Boingo" stay together in a sorted list.
You can see this live in action by creating a list of folders in Windows Explorer:
- Boi-Ago
- Boi-Ngo
- Boiago
- Boingo
Usually, you'd expect the list of folders sorted like above. But the special word sort technique outlined above produces the following result, which also matches what you've observed in your initial report.
- Boiago
- Boi-Ago
- Boingo
- Boi-Ngo
I can understand why you'd see this type of sorting behavior as a bug, but hope that the additional information reframes it more in the direction of a feature — a feature, which is admittedly not very helpful in your particular case.