Well to be precise deep stall happens rather on T - shaped tail planes. Like F-104. It happens during stall, when Elevator enters a shadow zone behind the wing, when there is no sufficient airflow. In J35 there is no such case - there appears different phenomena typical for double delta wing. During flight with high angle of attack - above linear part of wings CL/AoA characteristic - builds up a high energy state vortex. Same vortex - builds up on wing of MiG-29 and Su-27. The only difference is - that J35 being double delta has a problem with it. In some range of AoA horizontal steering becomes not effective. But all 3 planes make the same maneuver. Only on J35 it's not a fancy aerobatic stunt, but practical way of recovering from deep stall.
@DummyCatz "increase in pitching moment due to aerodynamic center moving forward at high AOA, causing a reduction in static margin, plus non-aerodynamic moments such as the rotational inertia." - that is definition of stall - and be please aware that for MiG-29 "reduction of static margin" appears already on AoA35°. (According to Low Rn Wind Tunnel tests). Vortex creates Lift, but does not build any negative aerodynamic moment. In other words does not create aerodynamic stability (aerodynamic damping forces).
Summary. Russians didn't invent Cobra maneuver. It was already known since J35 existence.
It's another post in these subject... I suppose every 10th guy who starts fly MiG-15 thinks that playing video-games makes him auto-cannon expert. And produces such post. Even Photos are similar.
303_Kermit's post in Pugachev's Cobra in a MiG-29? was marked as the answer