>>>>> "Ian" == Ian Dunn <dunni@gnu.org> writes:

    Ian>     I've got a few tasks that I don't want appearing in the
    Ian> daily agenda, so I tag them with agenda_exclude and set
    Ian> org-agenda-skip-function to skip any entries with that tag for
    Ian> my daily agenda:

    Ian> (defun id/org-skip-by-tag (&rest tags) (if (not (apply
    Ian> 'org-entry-has-tags-p tags)) nil (save-excursion
    Ian> (outline-next-visible-heading 1) (point))))

    Ian> (let* ((agenda-skip '(org-agenda-skip-function (lambda nil
    Ian> (id/org-skip-by-tag "agenda_exclude"))))) (setq
    Ian> org-agenda-custom-commands `(("d" "Day View" agenda ""
    Ian> ((org-agenda-span 'day) ,agenda-skip)) ("T" . "Tags View")
    Ian> ("Tn" "Nightly" tags-todo "nightly&TODO==\"TODO\""))))

    Ian> As you can see, I've got a second agenda view for my nightly
    Ian> checklist.  So here's my problem: the skip-function is unset if
    Ian> I try using the nightly view.

I went ahead and looked into this myself.  Looks like the issue is that the properties (lprops) are set using symbol properties with org-agenda-redo-command, which is buffer-local.  However, according to the elisp manual (at least for the upcoming 26.1 release), symbol properties aren't buffer-local; only the value itself is.  Thus, lprops are overridden by a new agenda.

I've created the following patch to address this.  The symbol property is used as a temporary variable, but the actual lprops are stored as a buffer-local variable to each agenda buffer.