Sorry, I know this should be reported in GitHub but it comes with a workaround:
It looks like since Kirby 5, URL appendices called `data` don’t allow setting a status. On an existing installation, the error was
Typed property Kirby\Toolkit\Iterator::$data must not be accessed before initialization
and trying this on a vanilla install with Composerkit, it was slightly different:
Value of type null returned from Kirby\Toolkit\Iterator::__get() must be compatible with unset property Kirby\Toolkit\Iterator::$data of type array
I assume that `data` is a reserved word now since that error did not happen on earlier instances. It shouldn’t prevent naming pages like this though.
Workaround
- renaming the page to something else than `data`
- setting the state
- renaming the URL back
Is this a known problem?