LinkedIn Senior Software Developer interview questions

One phone interview followed by an onsite with five rounds. There were coding, algorithms and one that focused on past experience. I did quite well in the phone interview. The interviewer complimented me in the end and assured me his input would be positive. I did well on three of the four technical interviews. In one of the design interviews I gave what I believed was the right answer, but clearly was not giving the interviewer what they expected. I could not get any guidance on what they might expect so we might discuss it. I felt I did well talking about past experience. It was hard to say since it was very subjective and the two interviewers were quite poker-faced. I did not get an offer. This is the second time I've interviewed there, done very well and still did not get an offer. I asked the recruiter to call me so I could learn what went wrong. The recruiter agreed that I did very well in the technical and design interviews. I was told that I did not have enough experience in design in my most recent jobs. This makes no sense. A big reason I left those jobs is I was not getting the opportunities I wanted. I don't expect to be doing high level design the moment I join the company. That's silly. The recruiter suggested I find a job doing high level design somewhere else and then apply to LinkedIn again. Fat chance. I'm done with them. I am an older engineer and wonder if this did not have something to do with it.