Black line on scanned file like no auto cropping

[HCB]

Hi, I bought Brother MFC-J480DW 2 weeks ago. I have noticed black line on scanned .pdf, .jpg and what ever.

I put a small piece of paper in the middle of glass. Then I pressed the scan button at the printer. Then the result has black line at edge of scanned area. It looks like it scanned displacement between "white scan pad" and "the glass."
However, auto cropping should remove the black line from the result.
When I initiate scanning from my PC by using of Control Center 4 and checked "Auto Crop" option, There is no black line there.
This black line appears only when scanning initiated at pressing scan button at my printer.

I know Cannon printers have auto cropping in this case, but I do not know on Brother printers

Do you think my machine has defect??

Thanks!!

 

[HCB]

I'll move this discussion to Brother forum. Because, it was concluded as the spec.