I have a problem some time ago. I don't know the cause:
I can't insert dates accentuated, for example Saturday (in Spanish it is Sábado). If I do it, I get:
<2024-09-28 s \341.>
Instead of
<2024-09-28 sá .>

And if I try to save the buffer, the minibuffer is open with "Select coding system" message.

I have no problem writing manually sáb. or sábado in the buffer, I have no coding problems.

If I do M-x describe-coding-system in the buffer, I get this:

Coding system for saving this buffer:
  U -- utf-8-unix (alias: mule-utf-8-unix cp65001-unix)

Default coding system (for new files):
  U -- utf-8 (alias: mule-utf-8 cp65001)

Coding system for keyboard input:
  U -- utf-8-unix (alias: mule-utf-8-unix cp65001-unix)

Coding system for terminal output:
  U -- utf-8 (alias: mule-utf-8 cp65001)

Coding system for inter-client cut and paste:
  U -- utf-16le-dos

Defaults for subprocess I/O:
  decoding: U -- utf-8-dos (alias: mule-utf-8-dos cp65001-dos)

  encoding: U -- utf-8-unix (alias: mule-utf-8-unix cp65001-unix)


Priority order for recognizing coding systems when reading files:
  1. utf-8 (alias: mule-utf-8 cp65001)
  2. iso-latin-1 (alias: iso-8859-1 latin-1)
  3. iso-2022-7bit
  4. iso-2022-7bit-lock (alias: iso-2022-int-1)
  5. iso-2022-8bit-ss2
  6. emacs-mule
  7. raw-text
  8. iso-2022-jp (alias: junet)
  9. in-is13194-devanagari (alias: devanagari)
  10. chinese-iso-8bit (alias: cn-gb-2312 euc-china euc-cn cn-gb gb2312)
  11. utf-8-auto
  12. utf-8-with-signature
  13. utf-16
  14. utf-16be-with-signature (alias: utf-16-be)
  15. utf-16le-with-signature (alias: utf-16-le)
  16. utf-16be
  17. utf-16le
  18. japanese-shift-jis (alias: shift_jis sjis)
  19. chinese-big5 (alias: big5 cn-big5 cp950)
  20. undecided


I have not that problem in emacs -Q
GNU Emacs 29.3 (build 2, x86_64-w64-mingw32) of 2024-03-24
Org mode version 9.8-pre