Why F5 send "Reset" after receive response in monitor traffic?

FYI Reset package have SEQ=46 >> sequence of HTTP GET / Ack=11316 >> seem like ack of HTTP /1.1 200 OK

Seem like F5 send Reset after got HTTP 200 OK (package NO 2966) and ignore FIN (package no 2967) from Server. Did anyone see problem or traffic misbehaviour from this dump?

monitor Config in bigip.conf is like this (ignore double backslash (\), we just use () in GUI)

ltm monitor http /Common/MOM-Monitor-Web-18888 {
    defaults-from /Common/http
    destination *:18888
    interval 5
    recv "FUSION MIDDLEWARE 11g"
    send "GET / HTTP/1.1\\r\\nHost: \\r\\nConnection: Close\\r\\n\\r\\n"
    time-until-up 0
    timeout 16