It may seem rather minor in the current big picture, dominated as it is by the current health emergency.
The two new problems are being recognised as essential fixes before the aircraft can be re-certified, which once a top priority is going to be a massive problem for Boeing and the airlines. Boeing wants them returned and delivered, the airlines are quite happy having them parked up free of charge, and many won’t even want them.
The problems are related to a set of ‘hypothetical faults’. These are issues that could happen in certain circumstances, however remote they might be, and the need to develop software code to manage them if they do.
The FAA are aware of the issues and Boeing is working on solutions.