usage issue with smerge mode

[laampui]

this is the init.el file

(load "~/.emacs.d/elpa/auto-rename-tag-20220616.1856/auto-rename-tag.el")
(require 'auto-rename-tag)
(add-hook 'html-mode-hook #'auto-rename-tag-mode)

Assuming this demo.html has some conflicts and smerge-mode turned on

when smerge-mode turned on, if I do smerge-keep-upper(C-c ^ u), the merge result will become this

if I do smerge-keep-lower (C-c ^ l), the merge result will become this