I haven't reached the bottom of this rabbit hole yet. Since I think I've spent all the time I had to spend in this issue for the day, here's where I'm at.
If I open my example file[1] with Org 9.3 and master (86fada6b5), and compare the overlays covering the hidden part of the first LOGBOOK drawer, like so: #+begin_src sh #!/bin/bash set -eu point=67 orgs=( "${path_to_org_9_3}" "${path_to_org_master}" ) for o in "${orgs[@]}" do emacs -Q -batch \ -L "${o}"/lisp \ -eval "(find-file \"logbooks.org\")" \ -eval "(message org-version)" \ -eval "(dolist (o (overlays-at ${point})) (message \"from %s to %s\" (overlay-start o) (overlay-end o)) (message \"%s\" (overlay-properties o)))" echo done #+end_src Here is what I get: > 9.3 > from 32 to 2015 > (evaporate t invisible outline isearch-open-invisible #[lambda gibberish > involving (org-show-context 'isearch)]) > from 67 to 262 > (isearch-open-invisible delete-overlay invisible org-hide-drawer evaporate t) > > 9.3.7 > from 32 to 2015 > (isearch-open-invisible delete-overlay invisible outline evaporate t) - The LOGBOOK overlay (from 67 to 262) vanished. - The isearch-open-invisible property of the "project 1" overlay (from 32 to 2015) changed from a lambda[2] to just delete-overlay. Again, not sure this shows there's an issue; for all I know Org 9.4 just works differently and nothing's wrong there. I hope someone can chime in and take it up from here; otherwise I'll resume my investigations sometime later. [1] https://orgmode.org/list/87eepuz0bj....@gmail.com/2-logbooks.org [2] Which I guess is the value of outline-isearch-open-invisible-function, set locally by org-mode in the major mode function?