jpeg – My scanner cuts my A3 leaving it black

but only at 2400 dpi.

I had fun with a project of analysis. Running a 16GB Mac2012 & i5 SSD.

an A3 Mustek S 2400 more capable of TADA! 2400 DPI @ A3 format
At maximum resolution, my scans are cut halfway. 🙁

ALL 2400 resolution scans are cut off. even those who are not so broad. but still A3 long.
Of course, not at the same length of data either …
Very frustrating!

Works at 300, runs at 600, 1200 and fails at 2400 …
Any thoughts some?
br /JPEG clippings