S-M-{<UP>,<DOWN>} on CLOCK timestamp

[Jorge P. de Morais Neto]

Keywords: org-timestamp-down org-timestamp-up

Hi.  Suppose the buffer has the following text:

* Task A
:LOGBOOK:
CLOCK: [2021-08-21 sáb 18:00]--[2021-08-21 sáb 18:10] =>  0:10
:END:

* Task B
:LOGBOOK:
CLOCK: [2021-08-21 sáb 18:18]
:END:

If I invoke M-S-<down> on Task B's clock-in timestamp, with point right
after the colon that separates HH from MM, then it correctly changes to
18:15 (decreases by three minutes), but Task A's clock-out timestamp
changes to 18:05---decreases by *five* minutes.

In my opinion, in this case the previous clock-out timestamp should not
change at all, because it was already less than 18:15.  But even if you
do think it should change, then surely you at least agree that it should
change by *three* minutes, just like Task A's clock-in timestamp.

This occurs on GNU Emacs 28.0.50 installed with
~guix package --with-branch=emacs-next=master -i emacs-next~
(upgraded last Thursday morning), invoked as ~emacs -Q~.  Note that on
my Guix-installed Emacs, an ~emacs -Q~ does load the emacs-org Guix
package (version 9.4.6).  Note also that my Org Mode has been patched
with Ihor Radchenko's patch to org-clock.el (attached to my previous
message), but it clearly can't influence this problem.

Regards

Emacs  : GNU Emacs 28.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.24, 
cairo version 1.16.0)
Package: Org mode version 9.4.6 (9.4.6-gab9f2a @ 
/gnu/store/yg6kjzigqyfzbkzj99xmwmv3nssvhvnq-emacs-org-9.4.6/share/emacs/site-lisp/org-9.4.6/)

-- 
- Disinformation flourishes because many people care about injustice
  but very few check the facts.  Ask me about <https://stallmansupport.org>
- I am Brazilian.  I hope my English is correct and I welcome feedback.
- Free Software Supporter: https://www.fsf.org/free-software-supporter
- If an email of mine arrives at your spam box, please notify me.