3524665 - CALL_FUNCTION_NOT_ACTIVE runtime error in MIGO transaction

Below runtime error occurs when using MIGO transaction. 
Runtime error details shows that the issue occurred when calling the FM /MERP/PM_INSP_LOT_SAVE_EX. 

"Category               Installation error
Runtime Errors         CALL_FUNCTION_NOT_ACTIVE
Except.                CX_SY_DYN_CALL_ILLEGAL_FUNC

Error analysis   

An exception has occurred in class "CX_SY_DYN_CALL_ILLEGAL_FUNC". This
     exception was not caught
    in procedure "IF_EX_INSPECTIONLOT_UPDATE~CREATE_BEFORE_UPDATE" "(METHOD)" or
     propagated by a RAISING clause.
    Since the caller of the procedure could not have anticipated this
    exception, the current program was terminated.
    The reason for the exception occurring was:
    The reason for the exception is:
    An attempt was made to execute the CALL FUNCTION statement in program
    "/MERP/CL_PM_INSP_LOT_EXCH_IMPLCP". The name of the function module to be
     called is "/MERP/PM_INSP_LOT_SAVE_EX".
    ""/MERP/PM_INSP_LOT_SAVE_EX" cannot be found in its function group though.

    Possible causes:
    a) Function module "/MERP/PM_INSP_LOT_SAVE_EX" has not been activated. This
     means that it
    cannot be found at runtime.

    b) The function library contains an incorrect entry for
     "/MERP/PM_INSP_LOT_SAVE_EX".

    c) The function module does not contain any code at all. Even FUNCTION
    ... ENDFUNCTION is missing."

SAP S/4HANA

KBA , MOB-APP-MAO-ERP , S4MERP/SMERP-Mobile Add-On integration to S4/ERP , Problem