TYPO3 Core

We upgraded an TYPO3 installation from 7 LTS to 8.7.6.

Now the display conditions in a plugin flexform, which worked fine under TYPO3 7 LTS, don't work under TYPO3 8.7.6.

After doing some research I found out, that the problem is in the EvaluateDisplayConditions class (https://github.com/TYPO3/TYPO3.CMS/blob/master/typo3/sysext/backend/Classes/Form/FormDataProvider/EvaluateDisplayConditions.php#L660).

Those loops only unset ...[$sheetName]['ROOT']... but not ...[$sheetName]['lDEF']['ROOT']... .

The display conditions work as expected, if I change the line linked above to:

unset(
    $result['processedTca']['columns'][$columnName]['config']['ds']
        ['sheets'][$sheetName]['lDEF']['ROOT']
        ['el'][$flexField]
);