  Diffuse intensities in the electron diffraction patterns of concentrated
face-centered cubic solid solutions have been widely attributed to chemical
short-range order, although this connection has been recently questioned. This
article explores the many non-ordering origins of commonly reported features
using a combination of experimental electron microscopy and multislice
diffraction simulations, which suggest that diffuse intensities largely
represent thermal and static displacement scattering. A limited number of
observations may reflect additional contributions from planar defects, surface
terminations incommensurate with bulk periodicity, or weaker dynamical effects
