Last year, the first photo of a black hole in Messier 87 was published:
It is quite obvious that about the lower half of the accretion disk is brighter.
This question (or rather, the asnwers) explain that it is caused by Doppler beaming. Since Doppler beaming partly constitutes of Doppler effect, I would expect to see a blueshift on the brighter areas and a redshift on the fainter areas; similarly to what the original rendering of the black hole from the movie "Interstellar" looked like:
So why is this not the case for the photo of the M87 black hole?