I have a hard time believing that this is a PHP bug.

#1: Try upgrading to a newer release.
#2: Here is what I tried to test your bug:
 create proc phpb
 as
 begin
   create table #phpb (id int, foo varchar(255))
   insert into #phpb values (1, "a")
   insert into #phpb values (1, "a")
   insert into #phpb values (1, "a")
   insert into #phpb values (1, "a")
   insert into #phpb values (1, "a")
   insert into #phpb values (1, "a")
   insert into #phpb values (1, "a")
   insert into #phpb values (1, "a")

    select * from #phpb

end

PHP script looks like:
<?php

$db = sybase_connect(...);

$qu = sybase_query("phpb");

while ($a = sybase_fetch_array($qu)) {
        var_dump($a);
}
?>

I got the exact same result from both PHP and isql...

Have you tried my example? If so, what results do you
have? It may very well be that I simply didn't create
a complex enough example, or something, but I don't
see a bug, so this'll be closed if you don't have
anything further to add.

no feedback...