I've been haveing the same prob. recently to some extent. It's June'43, and I'm patroling the Bismark Sea near Rabaul. I 'm useing ROW, RFB, and RSRD p3. I have been attacked several times now in the black of night. What I did that seemed to to stop it, was to turn my radar off, only makeing one single sweep per hour. I'm not sure if Japanese AC were equipped with radar, or radar detecting equipment at this point in the war, but this seemed to solve my continuous attacks at night.
Edit: Was just attacked again despite haveing radar off. So much for that theory.