What causes LeanTween tweens not cancelled on scene change?

LeanTween tweens are tracked globally and are not automatically cancelled when a scene unloads, so a running tween or its onComplete fires against objects that no longer exist.

How do I catch this when it only happens for some players?

Capture it automatically from the player's device with the full stack trace, the device and OS, the build, and a breadcrumb trail of what they did. That turns a vague complaint into a specific, reproducible issue you can fix without owning the hardware it happens on.

How to Fix LeanTween Tweens Not Killed on Scene Change Causing Errors

Quick answer: Cancel tweens on the relevant objects in OnDestroy or before loading a new scene, and avoid onComplete callbacks that touch scene objects after a transition.

After switching scenes you get a flurry of missing-reference errors from LeanTween callbacks meant for the previous scene's objects. The tweens outlived their targets. Cancelling them as the scene tears down stops the cross-scene firing.

How to fix it

1. Cancel per object in OnDestroy

Call LeanTween.cancel(gameObject) in OnDestroy() so any tween on that object stops when the scene unloads it.

2. Cancel before loading

Before SceneManager.LoadScene, cancel tweens that should not survive the transition, or call LeanTween.reset() to clear all of them.

3. Guard onComplete callbacks

If a callback must run, null-check the objects it touches; otherwise prefer cancelling the tween so the callback never reaches into a destroyed scene.

Catching the ones you can't reproduce

The hardest version of this to fix is the one you can't reproduce — it only happens on a player's hardware, OS, driver, or save state, under conditions that simply aren't present on your machine. A report that says “it crashed” or “it froze” gives you nothing to act on, so the bug survives release after release while quietly costing you players.

Automatic error capture closes that gap. Each failure arrives with its full stack trace, the device and OS, the build number, and a breadcrumb trail of what the player did right before it broke, so even a failure you have never seen becomes a specific, reproducible issue. Fold identical failures into one signature ranked by how many players each hits, and your worklist sorts itself worst-first instead of arriving as a stream of vague complaints.

This is where a tool like Bugnet earns its place. Its SDK captures every Unity error automatically with the full stack trace plus device, OS, memory, build, and game-state context, folds duplicates into one grouped issue with an occurrence count, and ties each to the build it first appeared on — so you fix the problem that hurts the most players first and confirm it is gone when its signature disappears from the next release.

The errors you never hear about are the ones quietly costing you players. Visibility turns them into a worklist.