core (patches): partially fixed jid caching: jid caching in Twisted use a dict (__internJIDs) which associate a jid as string to its jid.JID instance. But this caching doesn't handle mutability of the objects, resulting wrong jid returned when a modification is done (e.g. if resource is changed). This is a temporary workaround until the patch is proposed and merged upstream. note: this is a partial fix because the caching is also leaking memory (cf. https://twistedmatrix.com/trac/ticket/5122)