Quick answer: Unity 2D effector zone with a trigger child both firing OnTriggerEnter? Effectors register as colliders; trigger child also collides - place the effector on the same collider as the trigger.
Wind zone has a point effector + trigger zone. Player passing through fires enter event twice.
Combine effector and trigger
One collider; isTrigger=true; the effector references this collider. One event per entry.
Or guard the handler
Track a 'last entered' time; ignore re-entries within 0.1s. Defensive.
Audit layered colliders
Layered colliders fire independently. Each layer's handler runs.
“Two colliders means two events. Combine or guard.”
If you find double-fires in 2D physics, the layered-collider pattern is the usual cause. Audit; combine; the bug disappears.