TYPO3 Core

Thank you, we'll investigate!

I can't confirm that, neither in 13 nor in 14. just put

$GLOBALS['TCA']['fe_users']['ctrl']['label_alt'] = 'uid,usergroup';
$GLOBALS['TCA']['fe_users']['ctrl']['label_alt_force'] = true;

no matter if label_alt_force is set or not.

can you test that again on some clean sites or do you have more code like label userfunc?

can confirm. by using

$GLOBALS['TCA']['fe_users']['ctrl']['label_alt'] = 'uid,usergroup';
$GLOBALS['TCA']['fe_users']['ctrl']['label_alt_force'] = true;

and pressing save in the fe_user

can confirm. by using

$GLOBALS['TCA']['fe_users']['ctrl']['label_alt'] = 'uid,usergroup';
$GLOBALS['TCA']['fe_users']['ctrl']['label_alt_force'] = true;

and pressing save in the fe_user

problem however is something where else, debugging $labelCapability shows that the additionalFields got null for the uid field which is wrong.

I guess

public function getAdditionalFields(): array
    {
        return array_filter($this->additionalFields);
    }