a bug in mismatch graph

Homo sapiens H_Sapiens_Feb_2009
(loads ref seq automatically)
File > Open File... gsnap.4.bam
Map range box > chr21:22333333-22999999
Load Data
Load Sequence in View
right click gsnap.3
Make Mismatch Pileup Graph
there are two groups of data on the very left and the very right
zoom in on the left data to see detail, everything looks OK
now zoom in on the right data, it shows all the positions as mismatches
which is wrong (you can use a regular mismatch graph to compare).

File is found here: http://transvar.org/~hvora1/