If expectation is the simple one presented on the other page,
  ...
the search tree of the root can have expected-All nodes.

[example: node has zero-window search, does not succeed, but still expected-Cut,
so has expected-All successors (and due to search instability, may in fact turn
out to be Cut, but that’s irrelevant]

The expectation used by most engines is
  [second successor is expected-Cut regardless of first successor (so more
   confident in move ordering), and if unsuccessful zero-window proof of an
   expected-Cut then revise to expected-PV]
  [these two changes don’t have to go hand-in-hand]
which collapses not-expected-PV and will-attempt-zero-window-pruning, and
there are no expected-All nodes in the search tree of the root! (expected-Cut
are either pruned, so we never see their expected-All successors, or become
expected-PV)