exception when calling a contact and the contact disconnects in the meantime

try to call some other coccinella user, but instead of answering the call, the other user disconnects his client. Then trying to hang up the call, or dismiss the make call window end in the following exception:

can't read "session(,jid)": no such element in array
can't read "session(,jid)": no such element in array
    while executing
"set jid $session($sid,jid)"
    (procedure "do_send_set" line 5)
    invoked from within
"do_send_set $jlibname $sid $action $cmd $elems"
    (procedure "send_set" line 9)
    invoked from within
"$cmd $jlibname {} session-terminate ::JingleIAX::EmptyCB"
    ("eval" body line 1)
    invoked from within
"eval {$cmd $jlibname} $args"
    (procedure "::jlib::jingle::cmdproc" line 4)
    invoked from within
"::jlib::jingle::cmdproc ::jlib::jlib1 send_set {} session-terminate ::JingleIAX::EmptyCB"
    ("uplevel" body line 1)
    invoked from within
"uplevel #0 $ensamble($cmd,cmd) $jlibname $args"
    (procedure "jlib::cmdproc" line 6)
    invoked from within
"jlib::cmdproc ::jlib::jlib1 jingle send_set {} session-terminate ::JingleIAX::EmptyCB"
    ("eval" body line 1)
    invoked from within
"eval jlib::cmdproc {::jlib::jlib1} $cmd $args"
    (procedure "::jlib::jlib1" line 1)
    invoked from within
"$jstate(jlib) jingle send_set {} session-terminate ::JingleIAX::EmptyCB"
    ("eval" body line 1)
    invoked from within
"eval {$jstate(jlib)} $args"
    (procedure "::Jabber::Jlib" line 3)
    invoked from within
"::Jabber::Jlib jingle send_set $state(sid) "session-terminate" ::JingleIAX::EmptyCB"
    (procedure "::JingleIAX::SessionTerminate" line 6)
    invoked from within
"::JingleIAX::SessionTerminate"
    (procedure "::Iax::CmdProc" line 43)
    invoked from within
"::Iax::CmdProc hangupjingle"
    ("uplevel" body line 1)
    invoked from within
"uplevel #0 $phone($name,command) $args"
    (procedure "CommandPhone" line 7)
    invoked from within
"CommandPhone hangupjingle"
    (procedure "::Phone::HangupJingle" line 12)
    invoked from within
"::Phone::HangupJingle $state(line)"
    (procedure "::NotifyCall::HangUp" line 10)
    invoked from within
"::NotifyCall::HangUp .notifycall.f.call"
    invoked from within
".notifycall.f.call.hangup invoke "
    invoked from within
".notifycall.f.call.hangup instate {pressed !disabled} { .notifycall.f.call.hangup state !pressed; .notifycall.f.call.hangup invoke } "
    (command bound to event)