See if there’s an automation similar to the below shown is used. Purchase Part used in the PO has the Order Proc Type = Auto Release and Send  + automatic order processing is enabled there. 

To understand the complete automation, please refer the document attached in the following thread. 

Intersite Order Setup - Automating Transactions | IFS Community

Maybe you are using a similar setup? 

hI @Asela Munasinghe 

Thanks for your feedback,

currently we don't use this field and its blank .

any other setting..?

Hi @pramodka46 

as I know this is the only way in IFS App9 and 10.

On the supplier setup for the supply site and on the customer setup for the demanding site within the intercompany loop, there is a message setup for the various objects you want to pass back and forth between the sites.  The message setup for Orders is part of the connection.

There will also be matching setup on the Customer

However, one of the main benefits of the intercompany setup is to have automated orders, so if you want to revert back to manual setup, there is likely lots of things to change.  If you remove this messaging function which creates the automatic send, I believe you will also lose the ability to send manually as it relies on the same message setup for the orders that originate as a PO only, where in your case you are CO-PO-CO.

Might be useful to understand why manual control is seen to be better?  I usually find this type of intervention is due to poor data setup or management of order dates that results in unwanted or early orders - but I’m just guessing at what your underlying issue is.