bug#74198: 29.4; Newsticker reloads old items as new

[BP25 <bp25@riseup.net>]

In GNU Emacs 29.4 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.41,
cairo version 1.18.0)
System Description: Fedora Linux 39 (Workstation Edition)

PART A:

delete your newsticker folder
emacs -nw -Q --load .emacs
where .emacs contains:
--8<---------------cut here---------------start------------->8---
(custom-set-variables
 '(newsticker-frontend 'newsticker-plainview)
 '(newsticker-url-list
   '(("Weather London" "https://weather-broker-cdn.api.bbci.co.uk/en/forecast/rss/3day/2643743" nil nil nil)))
 '(newsticker-url-list-defaults nil)
 '(newsticker-retrieval-interval 0)
 '(newsticker-automatically-mark-items-as-old nil)
   )
--8<---------------cut here---------------end--------------->8---
M-x newsticker-show-news
M-x newsticker-get-all-news
M-x newsticker-show-news
Mark the items of the first (and only non-default) feed as old
M-x newsticker-show-news

Expected result: the items previously visible as orange stay orange.
Obtained result: the items previously visible as orange are white.


PART B:

Same as PART A except remove the line
'(newsticker-url-list-defaults nil)
from .emacs

Expected result: the items previously visible as orange stay orange.
Obtained result: the items previously visible as orange stay orange.


PART C:

Same as PART A except remove the line
'(newsticker-retrieval-interval 0)
from .emacs

Expected result: the items previously visible as orange stay orange.
Obtained result: the items previously visible as orange stay orange.


ANALYSIS: There must be some conflict between
'(newsticker-url-list-defaults nil) and '(newsticker-retrieval-interval 0)