World Composition basic physics question

Is there something different about the physics and collision setup for World Composition compared to a normal world? I am having an issue where an object that is in any World Composition sub level will vanish when I hit play if set to simulate physics. I can take any object in the same project and make it work fine on a level with no World Comp sub levels but if I then place that same setup object type in World Comp it will vanish on play. It seems to come down to physics, if the object is set to simulate physics it will vanish on play in a World Comp sub level, if i turn off physics, the objects stay in the level on play. The objects that vanish on play also vanish from World Outliner so I don’t think they are falling through the world. I did a few experiments to see what kinds of things happen in various conditions, a third person player will not vanish but it will start play under the map. Its like it doesn’t even have time to fall, I hit play and the third person character starts under the map and then falls.

Is there something basic I need to turn on or off to make World Composition tiles treat physics the same for all objects regardless of being in World Comp or not?

Thanks

I guess they were serious about that World Origin Rebasing being checked to On in the World Settings. I have physics again.