The HP Prime emulator seems to have difficulty with Zeta() of an odd positive integer, retaining the function call unevaluated even after Eval(). In a plot view such values show as "Undefined". What's going on? Zeta() is well-defined at these values and my WP34s (the real thing) has no difficulty evaluating Zeta(3) for example to be 1.20205...

Zeta() of an even integer is correctly handled returning the appropriate expression involving pi, and Zeta() of non-integral values is also correctly handled.