I had a very similar experience mentioned by earlier candidates. I was contacted by the recruiter regarding this position via Linkedin. Then I was scheduled for online interview on BlueJeans with one of their team members which went well. I got the call from their recruiter saying all the positive things about the interview and the feedback he got about me. Then I was given a take home project which took me around 4 hours to finish. I tried all my best to understand the app and add functionality to it. All the green tests etc. I got the reply back after 3 days saying "we have decided not to move forward with your candidacy at this time; it wasn't a decision that we made lightly". No feedback provided regarding the project at all. Candidates spend hours to do their projects and we get a line or 2 from them. I should have listened to what other candidates had to say about the process and should not have wasted my time on that project.