Why can't I see mutual friends on Facebook?

[yon]

Here goes...a friend has unfriended me but when I go on their profile it used to say we had 10 mutual friends however since yesterday it has dropped to 3! The mutual friends that were showing had their own friends list unhidden hence why mutual friends were showing with the friend that unfriended me. What I can't understand is that these mutual friends still have their friends list unhidden so why isn't the friend that unfriended me appearing in their unhidden friends list like before? I know that if both parties decide to hide their friend list then they wouldn't come up as a mutual friends but on this occasion it's only one party that has hidden their list and not the other!

[ErinX]

maybe that friend has unfriended a lot more people then you think or has decided to block some people