Help w/ nnimap-split-methods ?

[David Masterson <dsmasterson92630@outlook.com>]

I'm a couple of Emacs mailing lists using Gnus off of outlook.com using
IMAP.  It seems to work except that I still wind up with some Junk as
not all the mail messages are parsed by nnimap-split-methods.  My
variable setting is:

(setq nnimap-split-methods
      '(
	("mail.orgmode" "^\\(To:\\|Cc:\\).*emacs-orgmode@gnu.org.*$")
	("mail.emacs" "^\\(To:\\|Cc:\\).*help-gnu-emacs@gnu.org.*$")
	("mail.devel" "^\\(To:\\|Cc:\\).*emacs-devel@gnu.org.*$")
	("mail.misc" "")
	)
      )

With this setting, I have a few questions:
1. I still get Junk email, but I thought the above would put junk in
mail.misc.  Why is the Junk folder being created/used?
2. Some, but not all, messages that should be parsed by the regexps and
put into appropriate mail folders, but wind up in Junk.  Why?
3. Once in awhile, things do show up in mail.misc instead of Junk.  Does
that make sense?

-- 
David Masterson