evaluate expression (rpn) - return(30)

[Angus]

I would like to push this topic. It seems that it is unsolved for quite some time. Maybe someone understands it or a hp-insider will read this thread and can help.
I remember Han suggesting the method so it seems to me many got under the impression that this should be doable. The more confused I got when rprosperi named that an old problem. I wonder if hp is even aware of the thing not working or if they are ignoring that.

Is there any sollution or explanation mentioned in the old threads (I did not find too much) or are there new insights?