Game not letting me save.

I’m having a problem saving the game when doing 100% race length on career mode. 
it seems to only happen after pitting, but whenever I save whether that be save or mid session save it doesn’t work. If you save it says failed to save and I can either retry or continue without saving. If you retry you get the same message, if you press continue without saving you go back to racing. If you press mid session save you get the same issue. When pressing continue without saving you go back to the main menu. When loading back in it goes back to the grid before the formation lap. If you press load it says failed to load. This still occurs if I save before pitting as saving works fine before that. 
After completing the whole race from the start again when crossing the line normally there would be a radio message from the engineer and the ai would take the first turn before the race result is shown. This doesn’t happen. When crossing the line all the ai slow as normal but am still able to drive as normal the only way to progress after this is to press retire. 
any suggestions or fixes?