We have a Store procedure declare as a Local External Function in the Transaction object 

function long pr_generar_codigo(decimal cod_parametro,ref decimal next_serial_no) RPCFUNC ALIAS FOR "sbp.pr_generar_codigo"

in the update strart of the datawindow we have this code

  SQLCA.pr_generar_codigo(parametro,codigo)     

Codigo is declare as a decimal instance variable

in execution (in Appeon 2016) the when it reach the line it stop the execution of the event and all the lines after the calling are not executed, it return no erros and no error in the Appeon log.

as a workaround we did the following:

decimal ll_codigo 

  SQLCA.pr_generar_codigo(parametro,ll_codigo)     

codigo = ll_codigo 

and it solve the problem