Hp50g emu : graph abs(x)^3 gives negative y-values

[Gil]

On my EMU48, I want to graph the function
y=abs(x)^3.

But for negative x-values it gives
negative y-values on the graph and also for F6-Table.

Strange, because executing on the stack
'abs(x)' ENTER
-5 ENTER
'x' STO
EVALUATE
gives the right answer 125 (and not -125).

On my real HP 48 Gx calculator, the graph is correct for negative x,
when writing y=abs(x)^3.

What should I check to get positive / symmetric graph for y,
like a U-shape, and not a wrong S-shape?

Thanks for your help.

Gil