Star notes printed from February 1984 - June 1995 were printed with a 100,000 sheet standard, therefore, partial runs contained gaps.
To see an explaination of how these gap runs work, see this page.
There is some controversy over whether run #1 of Boston stars were actually printed. It could be possible that the BEP reported this incorrectly and they were actually the first run of $10's that appear not to have been printed.