All NavMesh behaviours missing when building anything else than Windows?

I recently updated the legacy NavMesh components using the NavMesh Updater.
Everything seems to work when building for Windows and when running in the editor.

However, when I make a build for any other platform, I see the warning “The referenced script (game object ‘Navigation’) on this Behaviour is missing!”.
I also see this for every game object with a NavMeshModifier Behaviour attached to it.

The production builds all use Asset Bundels, these include the scenes and prefabs that use these NavMesh Behaviours.

Like I said, this works fine on Windows or when running in the Editor, but whenever I test it on another platform (for example, Android) I get the above warning and the NavMeshAgents stop working.

Does anyone know what’s causing this and how to fix it?