Forum rules
An Activity Log is required for support requests. Please read How-to get an activity log? for details on how and why this should be provided.
When add a folder of files to the queue Handbrake sort the files by its own logic rather than what Windows Explorer does.
the number "10" is placed before "2", symbols are sorted lower than letters.
Amazingly, computers go by methods involving numbers we humans don't think about. And multi-digit numbers sort differently if their digits are spread over different columns.
As mduell points out, "1" comes before "2", but "10" also comes before "2", because the "1" is in the same column as the "2". If you want them to sort like you're expecting, you need to space the numbers out as " 1", " 2", "10", "11", "12" (note the space in front of the single-digit numbers). Alternatively, you can insert a zero instead of a space "01", "02" to make them sort the way you want.
So yes, it DOES follow the file name order, just not the one you think it should. Name the files correctly, and they'll appear how you think they should.