I have been processing some S2 images on a Mac using a fully updated v. 9.0.0, generating images using the band expressions 12/11, 11/8 and 4/3 for geology enhancements. This works perfectly on Mac OS but migrating to a PC (Win10), again with the latest and updated SNAP, the image using band expressions is bizarre and looks nothing like the Mac version (too red and seems to be sized differently if I compare with other RGB images on split screen. I have tried this now on two Macs and two PCs, same result as shown below:
On the Mac - panels from left RGB = 4_3_2, 12_11_2, 12/11_11/8_4/3
On the PC - panels from left RGB = 12/11_11/8_4/3, 12_11_2, 4_3_2
I am following exactly the same processing steps after resampling to band 2 on both platforms, hence my suspicion of a bug in the Windows version. Puzzling!