The open/close Syntax used in a post combined with the the first variant of [note ... something ... ] breaks the function of this plugin. You have to choose one syntax only in a single post.
It´s important for me, because I play with the thought, that I deinstall "Simple Footnotes" because of the usability of the syntax. The Look and Feel of this is plugin is better.
With a search and replace plugin I could make [ref]...[/ref] to [note]...[/ref], so that I´ll not loose my old footnotes from simple footnotes.