Doubt about velocyto run10x count exon and intron matrix how to deal with repeat barcode&UMI

[seqyuan]

as the velocyto run10x read the possorted_genome_bam.bam, but I found the bam file not exactly sortted by barcode and UMI, here is an example of possorted_genome_bam.bam:

I think if the reads have the same barcode&UMI, it should not be repeat count.