This happens on api call on endpoint for product update.
It's fixed by setting a different http version via curl_setopt
in file src/WooCommer/HttpClient/HttpClient.php after line 355
\curl_setopt($this->ch, CURLOPT_HTTP_VERSION, CURL_HTTP_VERSION_1_1);
or better calling runtime not to break vendor package in you calls
$api = new Client($url, $consumerKey, $consumerSecret, [$version]); $api->http->setCustomCurlOptions([ CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1 ]);
of course it's an hotfix and it should be refactored probably