phpMyAdmin-php81-4.9.10 got error Call to undefined function Symfony\Polyfill\Mbstring\iconv_strpos()

Question

when running phpMyAdmin-php81-4.9.10, got the following error

I have php8.1 with extension installed.

Fatal error: Uncaught Error: Call to undefined function Symfony\Polyfill\Mbstring\iconv_strpos() in /usr/local/www/phpMyAdmin/vendor/symfony/polyfill-mbstring/Mbstring.php:501 Stack trace: #0 /usr/local/www/phpMyAdmin/vendor/symfony/polyfill-mbstring/bootstrap.php(60): Symfony\Polyfill\Mbstring\Mbstring::mb_strpos('&', ';', 0, 'UTF-8') #1 
/usr/local/www/phpMyAdmin/libraries/classes/Url.php(331): mb_strpos('&', ';') #2 
/usr/local/www/phpMyAdmin/libraries/classes/Url.php(243): PhpMyAdmin\Url::getArgSeparator() #3 
/usr/local/www/phpMyAdmin/libraries/classes/Url.php(224): PhpMyAdmin\Url::buildHttpQuery(Array, true) #4 
/usr/local/www/phpMyAdmin/libraries/classes/Url.php(172): PhpMyAdmin\Url::getCommonRaw(Array, '?', true) #5 /usr/local/www/phpMyAdmin/libraries/classes/Core.php(749): PhpMyAdmin\Url::getCommon(Array) #6 /usr/local/www/phpMyAdmin/libraries/classes/Core.php(330): PhpMyAdmin\Core::linkURL('https://secure....') #7 
/usr/local/www/phpMyAdmin/libraries/classes/Core.php(353): PhpMyAdmin\Core::getPHPDocLink('book.session.ph...') #8 
/usr/local/www/phpMyAdmin/libraries/classes/Session.php(118): PhpMyAdmin\Core::warnMissingExtension('session', true) #9 
/usr/local/www/phpMyAdmin/libraries/common.inc.php(132): PhpMyAdmin\Session::setUp(Object(PhpMyAdmin\Config), Object(PhpMyAdmin\ErrorHandler)) #10 
/usr/local/www/phpMyAdmin/index.php(27): require_once('/usr/local/www/...') #11 {main} thrown in /usr/local/www/phpMyAdmin/vendor/symfony/polyfill-mbstring/Mbstring.php on line 501

I have checked that iconv has been installed.

php --ri iconv

iconv

iconv support => enabled
iconv implementation => libiconv
iconv library version => 1.17

Directive => Local Value => Master Value
iconv.input_encoding => no value => no value
iconv.output_encoding => no value => no value
iconv.internal_encoding => no value => no value