I'll bet the screw in the center of the air filter fell into the intake port, or one of the 5 screws holding the air filter assembly accidently fell into the intake plumbing.
The most probable,
The screw in the center may have been stripped and disappeared without the "mechanic" or "tech" being aware it was loose or missing when assembling or cleaning the filter. And ended up in the intake tract behind the air filter assembly.
Just my theory?