Mac OS X, update, "Invalid cookie header" messages displayed

when fetching available extensions the console shows some warning messages :

DATE org.apache.httclient.protocol.ResponseProcessCookies processCookies
AVERTISSEMENT: Invalid cookie header: "Set-Cookie: experimentaionè_subject_id=XYZ"

(from redmine: issue id 2843, created on 2020/06/06 by Matthieu Decorde)