Quick answer: Godot reverb works in the editor but disappears in the exported build? The bus layout is unsaved — the editor uses in-memory changes; the build uses default_bus_layout.tres.
A test build ships without the reverb applied to dialog. The bus layout was edited live but not saved before export.
Save Bus Layout
Audio → Save As: pick the project bus layout file (default res://default_bus_layout.tres). The editor uses runtime state; the exported game loads from this file.
Project Setting Path
Project Settings → Audio → default_bus_layout. Set the path to your saved bus layout. The build references this file at startup.
Effects Are Resources
AudioEffect instances are sub-resources of the layout. If you delete the layout file, the effects disappear with it. Keep the file in version control.
Verifying
The exported game plays audio with reverb / compression matching the editor. Effects toggle correctly via AudioServer.set_bus_effect_enabled.
“Bus layout edits live in memory until you save them to the .tres file.”
Save bus layout after every audio change — the “works in editor, missing in build” debug cycle is excruciating otherwise.