Interactive Brokers Senior Software Developer interview questions

Slow interview process and inept management team. Finished open ended OA coding exam based on OOPs principles. I enjoyed talking to Shri and Glen who were very knowledgeable and very nice to talk to. I was asked very good c++ questions on modern c++ features. Was asked to implement std optional like container and was asked one string algorithm question. My latter two interviews were very disappointing. One was a Russian guy who didn't want to be there and I could tell right from the beginning he didn't want me there. Second was a guy called Anthony who asked me how I solved a specific technical problem at work. He said he likes what he saw and gave me a positive signal but then came rejection. I have no idea what the rejection could even be on. It was a complete waste of time. HR didn't even give me any feedback.

The beginning of the interview process was a phone screening as usual. Then as a first round I got an email that contained a 60 minutes technical test with average questions.