How do you check the event position in the parallel event? For what you described, I think you use: $gameMap.event(eventId).pos(x, y)...
This is a default call to check event position on map and can be used for push/pull event, but not pickup event.
To check where a pickup event as landed, use: $gamePlayer.hasThrownEvent(eventId, x, y)
The example above will reset player and event position whenever player has thrown the event 8 at position x26, y19.