System error message displayed instead of designed message

(For reference, this is the same BPM as in my last topic: Job Receipt to Inventory not Make-to-Stock warning BPM conundrum - #5 by d_inman )

BPM checks for two conditions:

  1. The callContextClient.AssemblyName field is equal to the “ERP.UI.RcptToInvEntry” expression, And…
  2. Number of rows in …designed query… is more or equal to 1

Query is:

image

When conditions are true, then raise exception.