Essent Guaranty interview questions

Tl;dr: This place rescinded an offer, weeks after they had made it. Absolutely unheard of. Extremely scummy and not trustworthy people. The interview process was fine, until: They gave me an "unofficial offer" over the phone. I requested a higher salary, within a reasonable negotiating range. The hiring manager said that he may be able to do so-and-so inbetween, and that he'd take it up with higher-ups, which I said I'd definitely consider and appreciate. From there, he ducked my follow-up emails for about a week and a half, claiming they were having trouble communicating or that they were almost ready to respond. After that, he called me and said that in the intervening time, they had interviewed another candidate and they liked them more. I cannot stress enough: This has always been, and remains, utterly outside the realm of acceptability. His excuse, to the extent he offered one, was literally that, well, we've been treated badly too. (Apparently they had had candidates accept offers and then renege close to the starting date.) But it obviously goes without saying that those people's lack of professionalism doesn't make it acceptable for Essent to be so grossly unprofessional with someone totally different. What does it say that a company does this? If they were willing to do it during the interview process, who's to say that 3 months, 6 months, or even a year into a role, they aren't still out looking for someone to replace you? A place like this quite simply cannot be trusted.

It's a 30-minute zoom interview, and somehow fast-paced. It began with a self-introduction, and the interviewer asked about the proudest project/most interesting course in University and why/knowledge of mortgage insurance.