Unfortunately, one of the only ways to fix this particular Call of Duty: Black Ops Cold War split-screen problem is to shut the game off completely and re-open it. Since it happens pretty consistently after every match, this means Call of Duty players will need to completely close out of the game constantly if they want to use split-screen and actually be able to see their opponents. Obviously, this is not very convenient, and considering the severity of the bugs, it's surprising that it hasn't been addressed yet.