Instanda interview questions

I made it until final stage and it took 6 weeks for whole interview process for North America role. First 30 min call with Recruiter/HR, 1hr Technical and Competency interview, 2 Assignments, 1hr technical and competency interview again to review assignments and further deeper interview and final 1hr 41 min interview again technical and competency questions with hiring manager and team. Interview process was lengthy but interviewers were friendly, they made sure candidate do not feel pressured during interview and they really want to get to know you both as person and your professional skills. After almost one week of final interview they sent rejection email like most recruiters with no feedback. Why would you spend 1hr 41 min on last interview if you don’t want to select. Leaving no constructive feedback shows they don’t care about even serious candidate’s time and efforts who made through until final stage and their lengthy & intense process, also who spent alot of time to learn about your company and to prepare interviews. When you feel you almost made and start imagining yourself in that team, boom!!! you get generic rejection email. I understand rejection is part of process but candidate whole spent 6 week deserve to know what they lacked so they don’t feel it was just waste. Atleast now I am leaving them this feedback to provide feedback to serious candidates LOL