What causes a Godot additively loaded scene leaking because it is never freed?

Levels were loaded additively with add_child onto a persistent root, but switching levels added the new one without freeing the old, so instanced scenes accumulated in memory.

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 a Godot Additively Loaded Scene That Leaks Memory Because It Is Never Freed

Quick answer: When you manage additive scenes yourself, free the previous instance with queue_free before or after adding the next, since Godot only auto-frees the current scene on change_scene_to_file.

Additive loading via add_child gives you control but also the responsibility to free old content. Unlike change_scene_to_file, nothing frees the previous additive scene for you.

How to fix it

1. Free the old additive scene

Before or right after adding the next level, call queue_free() on the previous instanced scene so its memory is released.

2. Track your loaded scenes

Keep references to the additive scenes you instanced so you can free exactly the right nodes instead of leaking ones you lost track of.

3. Verify with the monitors

Watch the Object and Node counts in the editor's Monitors tab while switching levels to confirm old additive scenes are actually being freed.

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 Godot 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.

Reproduce it once with full context and the fix writes itself. The hunt is the expensive part.