Show Friends inconsistency


#1

Sometimes when I call the Twitter API for a list of friends, like this:
http://api.twitter.com/1/friends/ids.json?screen_name=gcvp
I get a list of friends, then I can call it again with a cursor:
http://api.twitter.com/1/friends/ids.json?screen_name=gcvp&cursor=13986572
and I get no results, because that cursor is the most recent friend

BUT, for some users, when I call to get the list of friends:
http://api.twitter.com/1/friends/ids.json?screen_name=chudson
then call passing the most recent friend as the cursor:
http://api.twitter.com/1/friends/ids.json?screen_name=chudson&cursor=914061

I get a list with one id:
“ids”: [
8393572
]
which was the first user that this user followed.
Why does this inconsistency exist?