Source &1 &2 and target &3 &4 have different revenue recog. categories

What causes this issue?

The source is a time-related revenue recognition item but the target is
a service-related revenue recognition item. In time-related revenue
recognition, the system uses the source item to determine the revenues
to be recognized. The determining factors are the value and defined
periods for this item. All the other items do not influcence the
revenue recognition process.

System Response

This message is for information purposes only. During revenue
recognition, both items are processed completely separately from each
other.

How to fix this error?

Check your copying control settings in Customizing for the target to
source document. Ensure that the required revenue recognition process
works correctly for both items. In other words:
Are the document types and item categories correctly maintained?
Have the correct revenue recognition categories been assigned to the
correct item categories?

Error message extract from SAP system. Copyright SAP SE.