the default bank or cash account and the account set as line items for bank and cash transactions do not appear as a default when creating the actual transaction. since there is no account selected when making the transaction, it is allocated to the suspense account.
this bug was noted when the Form Defaults feature was introduced and will be fixed in coming updates. you can read about it in the below topic.
till this issue is fixed you may select the correct account manually when recording a bank or cash transaction.