Short dumps on old FM with obsolete parms

[Sample, Rick]

Hi folks,

I have an old FM calling SWW_WI_CONTAINER_READ with an old obsolete parm that is now getting short dumps.

CALL FUNCTION 'SWW_WI_CONTAINER_READ'
  EXPORTING
    wi_id                    = l_activewi_id
    read_for_update          = 'X'
  TABLES
    wi_container             = container
  EXCEPTIONS
    container_does_not_exist = 1
    OTHERS                   = 2.

SWW_WI_CONTAINER_READ used to have this export parameter called: 
"read_for_update" (no longer used and obviously not for a long time but never caused issues) 
The FM compiles without warning, but does show as error in SLIN. When it was written, was not an issue. 

Now, we are in ECC6 for few years, and did a service pack upgrade over the weekend. (Gathering details on exactly what moved up) 

Is there some option that could have been turned on stronger checks on something like the FM interfaces?

Thanks,
Rick