Problems measuring camera SNR with darktable and Raw Therapee

Thanks for the raw file. I spotted one thing which might cause your issue. Your camera has two different greens. Amaze does not take this into account (only VNG4 does that).

Have a look at the screnshot. You can clearly see the typical pattern of two different greens on the left. On the right I set Green equilibration to 1 to remove that pattern.