valutils.exceptions.ValidationError: The images are not unique, please submit a unique image for each case.

Does anyone know what this error means? The only thing I changed in this submission is I thresholded the pixel mask values to 0 and 1 opposed to probabilitic determinants.

I encounted the same issue before, It happened for my case when the predictions had more than two files that were zero masks (no ICH segmented in CT scans).