Okay after a few more hours debugging this, I have some updates for you. I see PHP warnings in my local logs related to the custom child theme's e, you might want to check these
---> PHP 6. filemtime() /path/to/site/wp-content/themes/astra-child/functions.php:20
---> PHP Warning: filemtime(): stat failed for <em><u>versteckter Link</u></em> in /path/to/site/wp-content/themes/astra-child/functions.php on line 21
Here is the code that produces the PHP warnings:
$my_typgraphy_css_ver = date("ymd-Gis", filemtime( get_stylesheet_directory_uri() . '/typography.css' ));
$my_custom_child_css_ver = date("ymd-Gis", filemtime( get_stylesheet_directory_uri() . '/style.css' ));
The problem there is filemtime expects a server path to the file, not a complete URL. The best solution is to drop _uri() when passing the path to filemtime:
$my_typgraphy_css_ver = date("ymd-Gis", filemtime( get_stylesheet_directory() . '/typography.css' ));
$my_custom_child_css_ver = date("ymd-Gis", filemtime( get_stylesheet_directory() . '/style.css' ));
But that does not solve the problem with generic select field options, unfortunately. The same problem happens with Twenty Twenty One active, so it's not related to the theme as far as I go. So I am still investigating, but I believe I have found part of the problem and a potential workaround. In the expert mode builder, it seems that a space before and after the View shortcode in the generic field options is required. So the options line should look like this, wth spaces before and after the View so:
"options":[ [wpv-view name='institutions-as-options-for-other-views'] ]
But...the first time this View is placed in the options of a generic select field, it doesn't work. If you place the same View in another select field's options, it works! So the first implementation seems broken. For now, I have left the same View in all 3 generic select fields with dynamic options so you can see it working.
That leads me to suggest a workaround while my 2nd tier team continues to investigate. You can duplicate each generic select field, and give them different slugs. Place the same View of options in both generic fields, and hide the first field so only the duplicate is visible.
This was a tricky one, so it took longer than usual to diagnose. Hopefully my 2nd tier team can find out why this is necessary, and how it can be fixed. I've reported the issue and will keep you updated here as I receive more information.