#1166 Incorrect page size / Long pause between scans

[Silence]

1. Incorrect page size with the following configuration:
   = Kyocera ECOSYS M2540dn (as far as I remember, I didn't have problems with Samsung, but it's not certain).
   = TWAIN Driver, over the network. (No problem with the ESCL driver.)
   = Predefined settings (No problem with Native UI)
   = Any paper source
   = Bit depth: 24-bit Color (no problems with "Grayscale" and "Black and White")
   Instead of an A4 scan, I get a square. I've tried "US Letter", "US Legal", "A4", "A4 inverted", but I always get a square.

2. When I scan on a Kyocera ECOSYS M2540dn using the TWAIN driver, I get the characteristic beeping sound that the scan is complete, and I can immediately perform a new scan.
   When I scan on the Kyocera ECOSYS M2540dn using the ESCL driver, the beep does not occur until about 1-2 minutes later. During these 2 minutes, I cannot use the scanner using either TWAIN or ESCL driver.