Pixel got double after Master bias/flat/dark creation

[vkagnihotri]

Hello Sir

I use FLI 16803 CCD which have 9 x 9 micron pixel. Whenever I image raw data it shows FITS header correct as fig 1, where pixel shows 9 micron as native and 18 micron after bin. this looks correct.

But after master frame creation, 9 micron goes 18 and 18 micron goes 36. which is wrong see fig 2.

Regards
Vikrant