Why the RFC call for IDOC_INBOUND_ASYNCHRONOUS is working for connection.call() and not working for connection.fill_and_submit_unit()

[mandarinfish2010ca]

I have code working for below
results = SAPConnection.call(
'IDOC_INBOUND_ASYNCHRONOUS',
IDOC_CONTROL_REC_40 = idoc_control_record_table,
IDOC_DATA_REC_40 = idoc_data_record_table
)

but the same IDOC control and data records are not working for below call:
idoc = {
'IDOC_CONTROL_REC_40': idoc_data_record_table,
'IDOC_DATA_REC_40': idoc_data_record_table
}

unit = SAPConnection.initialize_unit(background=False)
SAPConnection.fill_and_submit_unit(
unit,
[("IDOC_INBOUND_ASYNCHRONOUS", idoc)]
)

and i received below error message:
Cell In[184], line 2
1 unit = SAPConnection.initialize_unit(background=False)
----> 2 SAPConnection.fill_and_submit_unit(
3 unit,
4 [("IDOC_INBOUND_ASYNCHRONOUS", idoc)]
5 )

File src\pyrfc\_cyrfc.pyx:1436, in pyrfc._cyrfc.Connection.fill_and_submit_unit()

File src\pyrfc\_cyrfc.pyx:1097, in pyrfc._cyrfc.Connection._create_and_submit_transaction()

File src\pyrfc\_cyrfc.pyx:1081, in pyrfc._cyrfc.Connection._create_and_submit_transaction()

File src\pyrfc\_cyrfc.pyx:2471, in pyrfc._cyrfc.functionContainerSet()

File src\pyrfc\_cyrfc.pyx:2525, in pyrfc._cyrfc.fillVariable()

File src\pyrfc\_cyrfc.pyx:2496, in pyrfc._cyrfc.fillTable()

File src\pyrfc\_cyrfc.pyx:2481, in pyrfc._cyrfc.fillStructureField()

ExternalRuntimeError: 20 (rc=20): key=RFC_INVALID_PARAMETER, message=field 'SEGNAM' not found [MSG: class=, type=, number=, v1-4:=;;;]