Sims disappearing from household

My sims keep disappearing from the household! Either they suddenly start walking off the lot into thin air and their icon from the left hand sides is gone - never to be seen again! 
Or I create a family and once I move them into a lot one of them disappears.

It’s not one drive as that’s not activated, have cleared cache files from ea app. I know its an ongoing issues EA are aware of but when will there be a fix cause its making the game unplayable!