I came across your question because my astro camera sensor is the same as the one used by your camera, and I needed to get the matrices for color conversion.

I read the paper you cited and everything seems to be logically correct. However, I encountered the same problem as yours - equation 75 does not hold. I got an example image for your camera from DPreview - studio shot comparison website: https://www.dpreview.com/reviews/image-comparison where you can select your camera model and download RAW image files as well as jpegs. I also got an example image for the camera that the author of that paper used (Olympus E-M1), and I found the same situation. Regrettably, the author did not attempt to test his equation 75 with the actual exif data from his image.

Then I read the Adobe DNG specification document (v 1.6.0.0) to try to figure out the reason of the discrepancy. The only extra matrices that are involved in the conversion from camera to XYZ_D50 are the ones called AB and CC -- Analog Balance and Camera Calibration matrices. The DNG exif data for the Fuji has AB = identity, and CC = diag(1.0347, 1, 0.9481), which is very close to identity. Disregarding CC (and AB which is ID), the equations given in the DNG spec doc agree with those in Rowlands' paper. I checked also including the CC matrix, but that does not make a significant difference, naturally.

So what is the conclusion? The DNG spec doc says that if the Forward Matrices are given in the exif data, one should use those to make the conversion to XYZ (and then RGB), whereas if they are not given, then one should use the conversion equation based on the Color Matrices. (In another forum someone conjectured that the color matrices are used just for normalization purposes, so we shouldn't expect them to be consistent with the forward matrices.)

An additional clue comes from the exif data in the JPG image downloaded from the same DPreview site. There, you find Red, Green and Blue matrix columns. Putting these together and transposing, you get a matrix that has to be a forward matrix, as it sends the vector (1,1,1) to the XYZ coordinates of D50. This is probably the conversion that was used to create the JPG image, and it is similar (but not exactly the same) to the Forward Matrices in the DNG file (probably interpolated to the exact scene white). According to https://www.strollswithmydog.com/determining-forward-color-matrix/, the matrix \$M_{\mathrm{sRGB}}^{-1} \cdot \mathrm{CAT}_{D50\rightarrow{D65}} \cdot \mathrm{ForwardMatrix}\$ is called "color matrix" in the DxOMark website https://www.dxomark.com/, as it takes white-balanced raw sensor data to sRGB. So some flexibility in the terminology should be accommodated. Fortunately, the above website (strollswithmydog) does make all the detailed calculations showing that his forward matrix agrees with the values given in the DxOMark website, so we can be pretty confident that the Forward Matrices are the ones to be used, if given in the exif data.