Simulation only runs from Frame 0

Hello all! First and foremost, the .blend:

Kindly ignore any missing textures.

Now the question: I want to delay a Rigid Body until fairly late in the animation. In brief, the “Prop_Stage” object should fall forward and over the edge of the “Prop_Ground” on cue.

I’ve keyframed the the object’s Rigid Body “Dynamic” property, and the delay seems to work as desired…

…so long as I only ever trigger Animation Playback (Alt-A) on frame 0. If I move the Start and End frames of the playback, none of the physics simulations run. Not the rigid body, nor handful of cloths I’ve got in the scene.

I’ve checked that the Rigid Body cache covers the total timeline.

Am I overlooking something? Do the cache values need to exactly match the Playback Animation range? I don’t want to wait all night on a cached wireframe animation that I’m going to edit anyway.