The statement ending balance is cleared after changing, deleting or inserting a bank account reconciliation line in the Payment Reconciliation Journal Page (Page ID 1290).

This could be ok if all lines have been inserted manually. 

But if the statement ending balance is set when importing an account statement, it should be retained. 

If a different statement ending balance really needs to be posted, the user already has the possibility to adjust the value directly before posting. 

It would be nice if the statement ending balance is not cleared, or at least it could taken any condition into account.