Under certain (currently unclear) circumstances, possibly related to Bug #26378 and Bug #26379, manual/loopback.py fails because the receiver receives two consecutive session-initiate stanzas from the gateway, followed by an error reply to an unhandled session-accept stanza; at this point the set of XPath patterns being matched only includes the session-ID of the *second* session-initiate. Bug #26246 might also be involved?
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