It seems like physics is not getting initialized properly if the first physics object a layout has EVER had is an event-spawned one.
If I've never hand-placed any physics objects in a layout, when I spawn some physics objects from an event on this layout, the event-spawned objects' X and Y positions become -1.#IND, -1.#IND before they get a chance to move.
Simply hand-placing a physics object in the layout seems to fix it. I can even delete the physics object afterward.
More long-winded version:
-I have a projectile (an arrow), with physics behavior. It exists in just one layout, and is not global.
-I have an action to spawn these projectiles when the "A" key is held, in an event sheet used in all my level layouts. Another object (a bow) spawns the arrows.
-Most of my layouts have never, ever had a physics object ever existing in them. That is, I've never added one to these layouts in Construct. Not the arrow object, not any physics objects at all. The first physics object these layouts will have ever had are event-spawned arrows.
In these particular layouts, when I spawn my projectiles, I can see them for an extremely short time (a split second, just barely enough time to see it), and then the projectile's X and Y position becomes -1.#IND, -1.#IND (as I can see in debug mode).
I can fix it by placing at least one physics object in the layout in Construct. After that, my physics projectile will then work properly in the layout.
I can even delete the physics object, save the cap, exit Construct, reload the cap, and physics is still fixed on the layout.
To fix it, I can either place the arrow object, or a completely new physics object, and delete the arrow/physics object again afterward. Simply manually placing a physics object on the layout, ever, allows physics to work in the layout.
Sorry, I forgot to say: Construct 0.99.42
Physics related bug, assigning to Davo.