This is actually not a bug. What you are running in to is php's auto-type conversion when you are building your array.

$a["11"] automagicly will become a numeric index of $a[11]. Due to the way that array_splice is designed, the array is completly changed, and thus the numeric indexes are reset.

If you wish to prevent this from occuring, prefix the numeric string with 0.

ie

<?
           $a["e"]="e";
           $a["r"]="r";
           $a["011"]="111";
           $a["022"]="222";

           array_splice ($a,0,1);
           foreach ($a as $k=>$v) {
               echo "$k=$v<br>";
           }
?>

will produce
r=r
011=111
022=222

-Jason