problems with "aoutoload" in 3.1.55

[Carlo de Falco]

I experienced the following strange behaviour with 3.1.5 for functions  
that are autoloaded from a .oct file,
but I am not sure whether it is a bug or I just don't understand how  
autoload is supposed to work

------------------------
 >> version
ans = 3.1.55
 >> pkg load nurbs
 >> which findspan
`findspan' is a function from the file /Users/carlo/octave/nurbs-1.0.0/ 
i386-apple-darwin9.6.0-api-v37/low_level_functions.oct
 >> which findspan
`findspan' is a function from the file /Users/carlo/octave/nurbs-1.0.0/ 
findspan.m
 >> autoload("findspan","/Users/carlo/octave/nurbs-1.0.0/i386-apple- 
darwin9.6.0-api-v37/low_level_functions.oct")
 >> which findspan
`findspan' is a function from the file /Users/carlo/octave/nurbs-1.0.0/ 
findspan.m
 >>
------------------------

anyway this worked differently in 3.0.5

------------------------------
 >> version
ans = 3.0.5
 >> which findspan
findspan is the dynamically-linked function from the file
/Users/carlo/octave/nurbs-1.0.0/i386-apple-darwin8.9.1-api-v32/ 
low_level_functions.oct
 >> which findspan
findspan is the dynamically-linked function from the file
/Users/carlo/octave/nurbs-1.0.0/i386-apple-darwin8.9.1-api-v32/ 
low_level_functions.oct
 >>
------------------------

any comments would be appreciated.
c.