I do have AB but its 'default' fan curve (which might have been changed by me sometime ago but I really do not remember though) does not have zero fan speed for temp under 50 (or 60) C. So, I know that curve is not really 'default'. Anyway, now that you mentioned it, an idea just came up (ie I might uninstall and then reinstall to 'get back' , sort of, the default fan curve).
For that case shown in that Chiphell thread, I am not a member there. But maybe you can contact the seller directly. If you read the thread, the seller made a response. That seller's name is his QQ account number (I cannot say with certainty but it is quite likely so). So, you can use QQ to contact him.
Edit: let me get it for you. He is ''QQ99671050''.