Hello everyone!  The manual says:


‘S-<UP>’ (‘org-timestamp-up’)
‘S-<DOWN>’ (‘org-timestamp-down’)
     On the beginning or enclosing bracket of a timestamp, change its
     type.  Within a timestamp, change the item under point.  Point can
     be on a year, month, day, hour or minute.  When the timestamp
     contains a time range like ‘15:30-16:30’, modifying the first time
     also shifts the second, shifting the time block with constant
     length. [...]

However, on the timestamp [2021-08-21 sáb 10:00-12:00], with point right
after the first colon, typing C-u 42 S-<up> results in
[2021-08-21 sáb 10:42-12:05].  The problem also occurs with S-<down>.

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), 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/)
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