SAP PI Can't send more than 9,999 IDOCS in one connection

Hi Experts,

I've got a FILE to IDOC scenario, the file contains about 12,200 IDOCS from type ACC_DOCUMENT.ACC_DOCUMENT03.

I'm working with PI 7.1, for some reason PI stops transferring the IDOCS after 9,999.

In SXMB_MONI i see the correct amount of entries (12,200), but sap gets only 9,999.

IDX5 shows only 9,999 entries.

In file sender adapter I  do content conversion to the flat file while declaring 'Recordsets per message' as 1, therefore creating a different message for each row in the file.

is there any limitation somewhere ?

Please help.