Double sample type for gene level copy number

Question

[matcap97]

Hello. I'm trying to find out the sample type of gene level copy number data from the TCGA-COAD project, when I download the manifest for primary tumour and normal solid tissue, it results that the files of the solid normal tissue manifest are also in the manifest of the primary tumour. In the end, I've got the same files for different sample type. Is it normal that the gene level copy number data of a solid normal tissue are the same for the same person but in the case of a primary tumour?

Maybe I'm missing something but with other types of data, this doesn't happen.

Thank you for your time, best regards.

Cappelli Mattia