Nothing noteworthy. Probably speaks of a memory leak in the CS' renderer. Restarting the app should take care of it.
Pretty much ! - It is usually caused by deleting an object or reference in the CS - the CS does a poor job of deleting the reference to that object and does not free up the memory location that it referred to so when the CS is closed and it does its checking it will find that memory location has not been freed and will give you that leaking error ( It is just a problem of memory not being freed correctly and will not effect anything in actual gameplay so nothing to worry about !)