[Maxima] string questions

[Sheldon Newhouse]

Hello,
 Why is there an '&' produced in 'substring' ?

Also, why is a substring not a string?  Are these bugs?

(%i5) string(hello);

(%o5) "hello"
(%i6) substring(%,1,4);

(%o6) ?\&HEL
(%i7) stringp(%);

(%o7) false

Also, note that the manual description of substring seems to show this 
(incorrect?) behavior.
(%i12) substring("substring",4);

(%o12) ?\&STRING

TIA,
 -sen