HP50g ABS value Graph

[Neve]

I’m surely doing something wrong, but I can’t get my 50g to correctly graph this simple f(x)=lx2-1l function. It graphs it as if the absolute value wasn’t there. I’ve tried everything I know, but nothing changes. My HP48GX graphs the right result…
What am I doing wrong? Could that be caused by a flag I set or unset?? Is it a bug?
I don’t understand.

Thanks for your help.