Default Keep losing root access.

Hi everyone I installed a pre-rooted 4.1.2 on my samsung galaxy s3 i747m, A few weeks ago I lost my root when I turned off the phone. When I started it back up my SuperSU was gone and when I run root checker it tells me that I do not have root. So I used a CFroot and rooted again, which work to root my phone, But sporadically I lose root and Supersu is removed. Is there anyway to fix this or a way to figure out what is causing my problem?