-M option reports the wrong number of reads processed about bowtie HOT 2 CLOSED

./bowtie-align-s -x indexes/e_coli reads/e_coli_1000.fq -m1 --best -S
# reads processed: 1000
# reads with at least one alignment: 699 (69.90%)
# reads that failed to align: 301 (30.10%)
# reads with alignments suppressed due to -m: 22 (2.20%)
Reported 677 alignments

./bowtie-align-s -x indexes/e_coli reads/e_coli_1000.fq -M1 --best -S
# reads processed: 1000
# reads with at least one alignment: 699 (69.90%)
# reads that failed to align: 301 (30.10%)
# reads with alignments sampled due to -M: 22 (2.20%)
Reported 699 alignments