What (actually) defines an Aten-class near-earth asteroid?
An Earth-crossing asteroid has either
an aphelion larger than Earth's perihelion ($Q \gt q_\oplus$, 0.983 AU),
or a perihelion smaller than Earth's aphelion ($q &lt; Q_\oplus$, 1.017 AU).
For those which have both, the semimajor axis $a$ determines whether it is an Aten or an Apollo - subject to change by a close encounter with Earth.

This Minor Planet Center
blog post
is consistent with the JPL table.
I think the diagram used the wrong inequality for Aten aphelia.