I have downloaded a couple of (Sentinel-2) raster files and would like to clip them down to be a smaller size. However, when I clip them the output file has a wider range of pixel values than the original file. For example, I clipped Band 2, which originally had values ranging from 0-1501. However after I applied the clip function reducing the total number of pixels the values ranged from 0-2132. I also tried mosaicking my (overlapping) files taking only the maximum value for each pixel to get rid of the 0 value areas and found the same thing to apply. I have tried this in QGIS 3.16.11 and also in 3.24.0 and no difference between the results.
Can anyone shed some light on what is happening here? I intend to use the pixel values to calculate NDVI so it is important that they are correct.