Parent page selectively shows pages under Gutenberg

[pojke]

This might be a long shot and possibly compatibility issue but I need help debugging from core team.

The bug
We have a number of pages that are created by different authors and under a different tree (multiple parents and children). Under Gutenberg, they randomly show in the field "Parent page" and by randomly I mean, when you go to a different page you get sometimes 5, sometimes 9, sometimes all of them.
I would blame compatibility first, except that:

• It works when switching to standard editor
• Under /wp-json/wp/v2/pages?per_page=-1&exclude=95&parent_exclude=95&orderby=menu_order&order=asc&context=edit reguest you always get a full list of pages so as long as that JSON is used in Parent page select field, there's definitely something wrong

How to reproduce
The thing is I wasn't successful so far. It's one website only, with one database. Moving to twentyseventeen and removing all the plugins is not fixing it. However, when I tried to reproduce it on a fresh install I was so far unsuccessful. Important - it's a network site.

I want to help but
I know how hard it is to work on a problem you can't reproduce so I can send someone the database directly or if I can get a little bit of help where to put breakpoints on JS to debug I can try to find an issue.

[chrisvanpatten]

Hi @pojke I believe this is fixed by #8908 which should be available in Gutenberg 3.6. If you're comfortable building from source, you might want to try the master branch and see if that solves the issue. Otherwise, 3.6 should be released soon, so hang tight :)

[chrisvanpatten]

Tagging as duplicate (of #8848), and I'll close this for now since #8908 provides a fix. We can always reopen the issue later if necessary, just reply and we'll get it opened!

[pojke]

I'd like to confirm that version 3.6 fixed it. Thank you 👍