Does this happen with the car off? If the car is being started when the running board deploys or stores, this will cause it to fail to deploy or store, as the car starting is taking most of the available power. If storing fails once you start to drive the board will retract at 5mph as a safety feature. If you avoid starting the car right when someone opens a door or within 3 seconds of a door closing this may solve your issue. I don't think they make this clear to owners in the documentation and likely why the dealer can't recreate the issue.
No it does not happen with the car off?