Hello, I am using gatk dragen map (dragen-os) to align my reads to reference sequence. Then I am using CalibrateDragstrModel to calibrate the quality scores. Whatever I am changing in parameters of this command it gives me the warning:

WARN CalibrateDragstrModel - there is not enough data to proceed to parameter empirical estimation, using defaults instead

WARN CalibrateDragstrModel - Not enough cases to estimate parameters, using defaults.

It seems it overrides my specified parameters. I searched a lot but unfortunately couldnt find any solution. Can you please guide me?

My command is like below:

./gatk/gatk CalibrateDragstrModel --down-sample-size 8000 -R ./reference/ref.fasta -I ./bam/N1.bam -str ./reference/ref-str_table.tsv -O ./output/N1_down_modified.txt

but it keeps giving me the above warning message.