2071664 - Query Error "Can not evaluate expression" - SAP IQ

On version IQ15.4 & IQ16, some various queries are hitting an ERROR , " dfo.cxx:#### … Can not evaluate expression".They have different causing factors, though  error message looks similar. Stack trace looks very similar too.

• Stack trace include the following functions:

         ..df_Exception..df_ErrorCode ...
         ..df_Exception::ThrowException ...
         ..dfo::ValidateOutputVectors  ...

• Error messages:   
  • Example-1 :    
    ** Non-Fatal IQ Internal Error Detected
    ** at dfo.cxx:11505  on thread 27500 (TID 28)
    ** Internal error at GROUP BY node: #03  Can not evaluate expression: A.EXEC_BAL`(3)
    ** Error detected at DFO #03 Group By (Sort) 
  • Example-2 : 
    ** Non-Fatal IQ Internal Error Detected                 
    ** at dfo.cxx:11439  on thread 22360 (TID 28)          
    ** Internal error at node: #09  Can not evaluate expression: CASE  WHEN
    ** Error detected at DFO #09 Right Outer Join (Hash PushDown)     
  • Example-3 : 
    ** Non-Fatal IQ Internal Error Detected
    ** at dfo.cxx:11257  on thread 27757 (TID 4)
    ** Internal error at node: #09  Can not evaluate expression: T2.t1_aa4
    ** Error detected at DFO #09 Union All

• SAP IQ 15.4
• SAP IQ 16.0

dfo.cxx, error -1001043, CR767912, 767912, CR768755, 768755, CR768832, 768832, CR769521, 769521, CR769521, 769521 , KBA , BC-SYB-IQ , Sybase IQ , Bug Filed