[O] latest org-mode ignores visibility property selectively

[Michael Maurer]

I'm currently using org-mode version 9.1.14, where everything
seemingly works fine.

The problem is, when I upgrade to the latest version via the packaging
system, one particular headline no longer folds and hides its
children, although the visiblity properties are identical to other
headlines, and the way its children are structured as well.

On startup the custom property gets ignored, it's not folded, and all
its children are visible. I've upgraded to the latest emacs version,
to see if that makes a difference, but the problem persists. Not sure
where or how I should start to track this problem down.

Here's the offending headline.

* DONE 2017 [462/462] abc,cde, efg, hij, klm
:PROPERTIES:
:VISIBILITY: folded
:END:
** DONE Dezember [34/34] abc, eds
:PROPERTIES:
:VISIBILITY: folded
:END:
   CLOSED: [2017-12-31 So 00:19]
   - CLOSING NOTE [2017-12-31 So 00:19]