ContentElements block not showing up in headless JSON

[carsten-wilhelm]

Describe the bug
I created a simple TYPO3 V13 site with a single ContentElement block.
I can add content block in backend and see the content element in backendview and rendered in frontend.
Adding the headless extension with default configuration gives an error - root cause is that the content element is not showing up in the list of page content, but instead a "null" is there

To Reproduce
I simply installed a fresh TYPO3 V13, added content blocks, created a simple content element block and added headless with default settings.
To see the JSON, I had to disable colPos grouping in headless (otherwise I just got an exception)

Expected behavior
Data from content block should be in JSON

TYPO3 Version
latest V13

Content Blocks Version:
composer install (friendsoftypo3/content-blocks 1.1.6)

[carsten-wilhelm]

I found a (temporary) solution - installing this extension made the content block show up in headless:
https://extensions.typo3.org/package/netzbewegung/nb-headless-content-blocks

[nhovratov]

Hi, thanks for testing Content Blocks with the headless extension! I for myself don't have any experience with the headless extension, but I know that some folks are eager to make it compatible (like the extension you linked). It looks like the transformation of the data array to Record object (and co) is troublesome. However, this comes mainly from TYPO3 Core (see Record Transformation API. If this is how the headless extension works, then this compat extension needs to be integrated into the main headless extension.