"Cannot compute median of an empty list" after reducing --gene-length to 1

[js72587]

I was trying to reduce --gene-length from its default value of 500 down to 1 to observe differences if we hypothetically included more genes, but am getting the error:

Invalid range Cannot compute median of an empty list

I also tried the values of 5, 10, 50, and 75. It wasn't until I tried 75 that the error stopped and the output file was produced. Could someone please explain why? I thought that reducing down to 1, 5, 10, or 50 would just include more genes; why is the "list" now empty (according to the error message)?

Thank you very much!