Editing paragraphs field settings returns 404 with php development server

Problem/Motivation

I have this strange behaviour on any local drupal instance. I start it in the web folder with the build in php development server: php -S localhost:8000

Now if I try to edit any paragraphs field, eg.

/admin/structure/paragraphs_type/manual_news/fields/paragraph.manual_news.field_news_entries

I get a 404 from the server.

[Fri Aug 13 12:47:39 2021] 127.0.0.1:55544 [404]: POST /admin/structure/paragraphs_type/manual_news/fields/paragraph.manual_news.field_news_entries - No such file or directory

If it runns on a real webserver, it works.

Anybody knows how to debug / fix this?

I checked the routing file, but it looks like this is hooked up soewhere under the hood?

If you prefere SO, you can also answer here: https://drupal.stackexchange.com/questions/305633/editing-paragraphs-fie...

Steps to reproduce

* Install a drupal 9 with paragraphs
* start it using the build in php development server: `php -S localhost:8000`
* create a new paragraph
* add a field to the paragraph - it will error out with a 404

Proposed resolution

Would be great if this would just work.

Remaining tasks

User interface changes

API changes

Data model changes