Function module MC_CREATE/UPDATE/DELETE_& not generated -> long text

What causes this issue?

A generation error occurred in the given function module as a result of
an inconsistency.

System Response

The system terminates generation of the given function module and logs
this error.

How to fix this error?

You can correct the inconsistency by activating the matchcode object
(the name of the relevant matchcode object can be found from the last
four letters of the function name). Call Transaction SE11, and choose
Utilities -> Other Dictionary objects -> Matchcode object -> Activate.
If the activation fails with an error message and you cannot correct
it, please contact SAP.
You can repeat the process interrupted by the error message (by
repeating the upgrade phase) after activation.

Error message extract from SAP system. Copyright SAP SE.