Had initial call with HR then got rejection saying we had very great response for this role moving forward with other candidate, I don't understand why do they took HR round then?

Had a recruiter call and waiting for their call. The recruiter was very friendly and explained me the interview process. Just asked me one question: How does your experience aligns with the Position you've applied?

Applied online, about a week later received an interview for phone screen. Amazing recruiter during the phone screen, probably one of the best I’ve seen, answered simple generic behavioral questions. Got invited to a one hour interview where I was I given two coding questions. The first question was a Java question asking to find the green ball. Very confusing at first in my opinion, they need to reword that. Essentially, given a list of Ball objects you need to find the green ball with the help of a method that identifies that a green ball exists in the list. The way to solve it is through divide and conquer. Overall I was able to come up with a solution but knew my process in solving it was bad so getting another interview was not going to happen. Second question was a typical HTML/CSS front end question where I had to replicate a picture of a UI, in my case it was a simple looking navigation bar, it was pretty easy. The interviewers were nice and helpful but like I said that first question is confusing so trying to understand them explain it was just nerve-racking. Unfortunately, got too nervous and bombed the first question but aced the second and within a week later I got a rejection email.