Binder on client side randomly fails subscription

Jun 10 06:39:35 m3ulcb afbd-demo-app@0.3[3421]:  ERROR: Failed to client_call_search_unlocked [/usr/src/debug/af-binder/guppy+gitAUTOINC+f878e8026a-r0/git/src/afb-proto-ws.c:517,client_msg_call_get]
Jun 10 06:39:35 m3ulcb afbd-agl-demo-app@0.3[3421]:  ERROR: Ignoring subscription to event [/usr/src/debug/af-binder/guppy+gitAUTOINC+f878e8026a-r0/git/src/afb-proto-ws.c:558,client_on_event_subscribe]

/* get event from the message */
static int client_msg_call_get(struct afb_proto_ws *protows, struct readbuf *rb, struct client_call **call)
{
    uint32_t callid;
    /* get event data from the message */
    if (!readbuf_uint32(rb, &callid)) {
        ERROR("Failed to readbuf_uint32");
        return 0;
    }
    /* get the call */
    *call = client_call_search_unlocked(protows, callid);
    if (*call == NULL) {
        ERROR("Failed to client_call_search_unlocked");
        return 0;
    }
    return 1;
}
// afb-proto-ws.c

ExecStart=/usr/bin/strace -o /home/0/strace.log -P /usr/bin/afb-daemon /usr/bin/afb-daemon \
	--name afbd-demo-app@0.3 \
	--rootdir=/var/local/lib/afm/applications/demo-app/0.3 \
	--workdir=/home/%i/app-data/ns-demo-app \
	--verbose \
	--verbose \
	--monitoring \
	--port=31012 \
	--token=HELLO \
	--roothttp=. \
		--ws-client=unix:/run/user/%i/apis/ws/demo-service \
	--exec /var/local/lib/afm/applications/demo-app/0.3/demo-app @p @t

[gdb]
qml: afbws: sent: [2,"9955052826553583","demo-service/subscribe",{"event":"engine_speed"}]
qml: afbws: sent: [2,"7415119148790836","demo-service/subscribe",{"event":"vehicle_speed"}]
qml: afbws: sent: [2,"24231125647202134","demo-service/subscribe",{"event":"gear_selector_position"}]
qml: afbws: received: [4,"9955052826553583",{"jtype":"afb-reply","request":{"status":"unknown-api","info":"api demo-service not found (for verb subscribe)","uuid":"21000bbb-0e53-497a-8a5f-da56330ad7f2"}}]
qml: afbws: received: [4,"7415119148790836",{"jtype":"afb-reply","request":{"status":"unknown-api","info":"api demo-service not found (for verb subscribe)"}}]
qml: afbws: received: [4,"24231125647202134",{"jtype":"afb-reply","request":{"status":"unknown-api","info":"api demo-service not found (for verb subscribe)"}}]