What happens is that someone starts out with Credit Card activities but they are using the wrong Transaction Type. Look in that register, on the left. For instance, someone started out as setting up a Bank Type account, and then entered the spending as CHK and credits as DEP. Then, someone edited the Account Type to change it from Bank to CC.
Now certain transaction types are Invalid and will not open. As long as you leave them be, you are fine. What they should have done is dealt with their error more properly, such as making one Credit Card Charge or Credit entry that lists the erroneous bank-type as the Expense detail, to make Banking = 0 and Transition to the CC account using the proper entry types.