TYPO3 Core

When working with a single select field in the form engine, with its localization mode setting set to defaultAsReadonly, the selected value from the localized children elements will not be correct.

With the following TCA configuration:

'event' => [
    'label' => "Select Single Element",
    'l10n_mode' => 'exclude',
    'l10n_display' => 'defaultAsReadonly',
    'config' => [
        'type' => 'select',
        'renderType' => 'selectSingle',
        'items' => [
            ['Label A', 'A'],
            ['Label B', 'B'],
        ],
    ],
],

I get the following rendering:

Root element

Translated element

In the translated element, the selected value should be Label B.