WP-34s, bug, or my mistake

[Nigel (UK)]

ENTER disables automatic stack lift so that, for example, typing 6 ENTER 3 into an empty stack leaves the stack as 3 6 0 0 rather than as 3 6 6 0. This is what happens in your first example. It's quite normal, I think; Free42 behaves in exactly the same way and I think that other HP RPN calculators do too.

From your second example I deduce that EXIT re-enables stack lift. I didn't know that!

Nigel (UK)