I have shared a tiff file with a friend and was taking him through Siril.
We both have Windows 10 and the latest version of Siril.
Going to histogram transformation there are 2 peaks, one RG and 1 B with considerable separation
On my PC I open the file (Rosette Nebula). In RGB autostretch view the screen is bright blue with the stars showing but in histogram view the nebula shows nicely
He gets the blue autostretch view but only a white screen in histogram view.
If I apply color calibration (either color calibration or photometric) the histogram peaks merge and I can apply autostretch with great results.
On his computer color calibration leads to a fragmented histogram with many peaks and auto stretch does not work.