Hi Robin,
Since you mentioned that Payment transaction appears in TJ04 also appear in TPM20, would it be possible to include the Payment reference field, which should show the Payment request number?
You can then check weather these payment reqeust are still open in F8BT.
The account you put in F111 should be Payment request clearing account, which should be configured in IMG.
Hope that this helps.
Cheers
Taro