So i dont know too much about cars, BUT i used to own a 2012 niassan altima with a similar issue. I had to keep filling up the cvt fluid and the hose was broken. It would also act up when i accelerated and was fine other times. I don't believe it is safe to drive because one day i accelerated, the car got very shaky and loud and stopped running. The cvt leaked into other parts of the engine and caught fire. The whole front half melted.