Dear Marco,
It’s correct and Not correct!, Correct, because technically the operator runs smoothly without any error,
and not correct, because I just found applying subset directly out of *,xml resulting subset the required bands, and keeping the size of the image as you can see below,

However, applying subset (for bands) within *.xml leads to subset the image or required band, because the number you referred to within the *.xml I provided to you
Is essentially within the operator as default number, following is another *.xml file has only three operators read, subset and write, as you can see, the number 1098 is already available as default,
Hope to correct this, to be the whole size of the image, and works exactly same to the subset operator from main tab raster.
Also this is the original size of each bands in the original image,

When resample to 20, and then subset the required band the operator shouldn’t take the size of the bands for instance 10 m, NOROW, NCOLS, or decrease the size accordingly to be applied and affected the real size of the image!
This opinion is out of the scope of this problem, and general,
If you remember in my last visit to ESRI, my opinion was to improve the SNAP already exist instead of adding more options and operator, delay is better than error.