C-c C-* causes "org-element--cache: Unregistered buffer modifications detected."

[Max Nikulin]

Another case of

Warning (emacs): org-element--cache: Unregistered buffer modifications 
detected. Resetting.
If this warning appears regularly, please report it to Org mode mailing 
list (M-x org-submit-bug-report).
The buffer is: c-star.org
 Current command: nil
 Backtrace:
nil
Org main, Emacs-26.3

c-star.org file:
---- >8 ----
Ф Put cursor on this line and hit =C-c C-*= to make it a heading
---- 8< ----

Notice a Cyrillic letter that causes a problem with `org-ctrl-c-star'.