Quick answer: Construct 3 physics object dropping to zero velocity after disabling collisions? Disabling collisions removes the body from the world entirely - use a filter mask instead via Set Collision Mask.
Pickup item briefly disables collision so the player phases through. After re-enabling, the item is stationary even though it should be flying.
Use collision mask
Set the object's collision mask to a value the player's mask doesn't intersect. The body stays in the simulation; only player collisions are filtered.
Or save and restore velocity
Before disabling, store self.physics.velocity_x/y. After re-enabling, restore. Hacky but works without changing collision strategy.
Avoid Physics > Apply Force at zero velocity
Pushing a stationary body with continuous force creates non-deterministic motion. Use impulse instead.
“Disabling collision removes you from physics. Filtering keeps you in.”
For pass-through objects, the filter pattern is more reusable. Three filter groups (player, enemy, environment) covers most indie games.