# $eventscores is an arrayref to an array of arrayrefs.
# everything works fine until the last while iteration
while ( $i <= $#{$eventscores} ) {
		$rider_id = $eventscores->[$i]->[0];
		while ( $eventscores->[$i]->[0] == $rider_id ){
			push (@scores, $eventscores->[$i]->[2] );
			$i++;
		}
#...more code.. unrelated to loop
}

##</code><code>##

$array_count = $#{$eventscores}

##</code><code>##

while ($i <= $array_count)