There is a substantial issue with Paper Trading Accounts where a split occurs in a security but the account holdings are not updated to reflect the split. In addition, the old symbol is then frozen in the account, unable to be liquidated. I suspect this happens because with the split a new CUSIP is created for the split security and the old CUSIP is rendered invalid. As the paper trading account does not update to the new CUSIP the split symbol is orphaned.
The preferred remedy is to have Paper Accounts correctly handle the split. An alternate remedy would be to allow the orphaned security to be liquidated at the last posted price. This would at least allow the paper account to be used without having to reset the entire account.
A search of the forum shows this issue reported by other users. I am not aware of and have not found a workaround other than doing an account reset and that is an unsatisfying solution. For development reasons I need a history of trades in the account and I do not wish to start over creating a new history.