okay, I do:
/buddy note Ruby "test"

it works

I do :
/buddy note Icarus "test"

and I get :
[Fri Nov 19 22:48:19 2004] ffffffBuddy system internal error; Icarus is apparently not your buddy?
[Fri Nov 19 22:48:19 2004] ffffffNote sent to Icarus.

Also note, that Icarus is my buddy and I get notices when he logs on and off.....

Is this consistant or a one-time event? Is it just with Icarus or with other players on your buddy list? If a one-time event, it was an internal error that properly rectified itself. If it happens all the time, that's a bug.

Consistent, all the time.
Haven't tried spamming everyone on my contact list though

Hmm. Your buddyship must be one-way with Icarus, and you shouldn't be able to leave notes for him, then. I'm pretty sure he isn't getting any notes you're leaving for him. If you do a /buddy list, is he listed?

yep, he's listed.