Error - A proper workflow definition could not be found.

[User3]

When receiving an inbound IDoc we are facing the error below:
Error - A proper workflow definition could not be found.
Message no. APPappl_mm_comp_wfl028

In my case the PO is created, then approved with WF. After approval, IDoc is sent to exsternal system and ORDRSP is received back in S/4, but here we are facing te below error.

I have already checked note 311167 and 2680572 but my case is different. For example, if we change the same PO manually, it will retrigger the WF and go for approval.
So we are facing the error even with a valid WF, but only in case of inbound IDoc for ORDRSP.

By the way, we deactivated the 'Automatic Release of Purchase Order' as was not needed.

Please help me undestand what we are missing.