I knew someone who was hired, given a letter of offer and attended his first few weeks of training. They walked up to him two weeks later and said we don't actually need your position right now but would you mind waiting until we call to set something up? On top of that, they bungled his pay.
An outlier I thought.
Then I went through the hiring process, nobody knew what anyone was going. I showed up to shadow for a day, nobody knew I was coming despite planning it all out and scheduling the day with a number of different people. I suddenly realized I was overqualified for the job, telling the guy I was shadowing what he needed to do, despite my limited familiarity with the interface.
A few weeks later, after another 3 interviews, they told me I wasn't what they were looking for because I told them I wanted to get out of my current job (one that had broken some promises to me)
Another person I went through the hiring process with was never actually onboarded. Like my other friend, she was given a letter of offer, and everything sort of fell apart at the end of the day.