Apple Biosensor Engineer interview questions

I was contacted by an Apple recruiter. I then had a phone screening with the hiring manager that went well. After that, II received some technical exercises that I had to work out within 2-3 days. Another recruiter then followed up and scheduled the on-site interviews. Interviews were both technical, as well as personality and program management oriented. My 1-1 interviews went very well, and I was very surprised I didn't get an offer. I asked about the reason and for some feedback, but didn't get any response. I am confused to this day.