US Bank repurposed the assistant branch manager role because they no longer have operational, non customer facing duties. If your friends were just hired/promoted they still have their job with a different title. No one was walked out the door-they were given a different FULL TIME position. Part time is under 30 hours and while they got rid of 40 hour tellers they were changed to 38 hours.
Exactly what @11GF83tQ-gfw said.