Unable to log in to phpMyAdmin 5.1 using cookie authentication

Running phpMyAdmin v. 5.0.2 and it works fine.

Downloaded 5.1.0-rc1, unzipped it to public_html and added server by phpMyAdmin/setup.

Also tried to manually edit the configuration.

When I try to log in by password I only get routed back to the log in page. No errors.

More specifically:

1. Enter credentials

Apache logs show a 302, so not sure if that is a clue:

127.0.0.1 - - [13/Jan/2021:04:45:55 +0100] "POST /~user/phpMyAdmin/index.php?route=/ HTTP/1.1" 302 1554 "-" "Mozilla/5.0 ..."
127.0.0.1 - - [13/Jan/2021:04:45:55 +0100] "GET /~user/phpMyAdmin/index.php?route=/&route=%2F&lang=en HTTP/1.1" 200 6295 "-" "Mozilla/5.0 ..."

Nothing in MySQL logs.

Any idea what could be the issue here?

v5.0.2 config.inc.php:

declare(strict_types=1);
$i = 0;
$i++;
$cfg['Servers'][$i]['host'] = 'localhost';
$cfg['blowfish_secret'] = '.KmeninsAmd6354s^asdk?\'=DEfaeafakm7as';
$cfg['DefaultLang'] = 'en';
$cfg['ServerDefault'] = 1;
$cfg['UploadDir'] = '';
$cfg['SaveDir'] = '';

v5.1.0-rc1 config.inc.php:

$i = 0;
$i++;
$cfg['Servers'][$i]['host'] = 'localhost';
$cfg['Servers'][$i]['port'] = '';
$cfg['Servers'][$i]['socket'] = '';
$cfg['Servers'][$i]['auth_type'] = 'cookie';
$cfg['blowfish_secret'] = '.KmeninsAmd6354s^asdk?\'=DEfaeafakm7as';
$cfg['DefaultLang'] = 'en';
$cfg['ServerDefault'] = 1;
$cfg['UploadDir'] = '';
$cfg['SaveDir'] = '';

Using auth_type http and config works fine.

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