Deleted the notebook and note, tried creating folder "Business" and it changed into "Business (249408)". Tried renaming this folder to just Business, and it gave an error that said that notebook already exists. Deleted it, tried creating folder "Business", turned into "Business (327944)". Same problem with not letting me rename it into "Business". Tried creating folder "business", said that notebook already exists, but when I changed the text to "Business", it let me create it without a number.
Deleted that, created "Business" again, and I noticed it successfully creates it but then in the notebook list it flashes and then changes to, in this last case, "Business (505963)". Still can't create "business" because it says that notebook already exists, but as soon as I change the case to "Business" it lets me create the notebook (before adding a number to the end of the name).
Just tried in the Web app and it does the same thing. Not a big deal, just interesting that this is happening. The test note kind of worried me someone, maybe Evernote, had added a note to my account, but maybe it's just an automated thing related to the bug.