TYPO3 Core

Dear typo3-team,

with a site with a umlaut-domian i get following exception in the /typo3/var/log/typo3_*.log

ue, 15 Nov 2022 11:16:37 +0100 [CRITICAL] request="9c6573d6f9fda" component="TYPO3.CMS.Core.Error.ProductionExceptionHandler": Core:
Exception handler (WEB: BE): GuzzleHttp\Exception\RequestException, code #0, file /html/typo3/vendor/guzzlehttp/guzzle/src/Handler/Cur
lFactory.php, line 211: cURL error 3: (see https://curl.haxx.se/libcurl/c/libcurl-errors.html) - {"mode":"WEB","application_mode":"BE
","exception_class":"GuzzleHttp\\Exception\\RequestException","exception_code":0,"file":"/html/typo3/vendor/guzzlehttp/guzzle/src/Hand
ler/CurlFactory.php","line":211,"message":"cURL error 3: (see https://curl.haxx.se/libcurl/c/libcurl-errors.html)","request_url":"htt
ps://www.xn--freie-whler-schorndorf-64b.de/sitemap.xml","exception":null}
~

The mentioned url with the already transformed domain-name for the curl call is:
https://www.xn--freie-whler-schorndorf-64b.de/sitemap.xml
The original url before the transformation is not mentioned in the exception, but so it is:
https://www.freie-wähler-schorndorf.de/sitemap.xml

That means:
cURL is getting an error 3; according to https://curl.se/libcurl/c/libcurl-errors.html this error means:

CURLE_URL_MALFORMAT (3)
The URL was not properly formatted.

But, the site with the umlaut-domnain otherwise is correct. All pages are reachable in all browsers. Just for the sitemap Typo3 does an internal call with cURL via guzzle, this one then fails for an unkown reason.

The error does only appear on [some?] umlaut-domains.

Any ideas?