AC Horn Manufacturing interview questions

I had 1 one phone interview and 2 in-person interviews with AC Horn manufacturing for their mechanical engineering position. After the second interview the hiring manager verbally offered me the job and gave me a start date. He even told me to put in my two weeks notice at my current company. After a week of waiting to hear back from HR I contacted them and was told he was still interviewing final candidates. That struck me as odd because he verbally gave me an offer and a start date. It turns out he didn’t clear it with HR and didn’t have the authority to give me the offer. He preceded to lie to HR and say I was never offered a job. Needless to say I looked like a fool. I almost put in my two weeks notice after the last interview but I wanted to wait for the written offer and I’m glad i did. After a month I finally heard back saying they went a different route and would like to consider me for future positions but I made it clear I never wanted to be considered for a position at that company again.