TYPO3 Core

See attached file for example configuration. The responsible code can be found in TYPO3\CMS\Backend\Form\Element\SuggestElement::getNestedDsFieldConfig().

1. The foreach loop reaches the settings.subelements field.
2. The method is called recursively for the subelements item configuration.
3. It returns the field configuration for the nested content field, which is required for the suggest.
4. The foreach loop continues with the settings.check field, overwriting the field configuration with an empty array.

To fix this a break should be added at step 3 if configuration is returned (not empty array).