Like a previous writer, I too have a bead of water around the entire perimeter of the waste seat at the bottom of the sink bowl after normal draining with new bathroom faucet/drain combo I have installed. I tried tightening it a bit more (to bend the waste seat more toward the center of the hole), but its fairly tight already and I’m concerned I could over tighten this plastic fitting and have an instant regret. Is it a problem if the bead of water remains?
You probably used the heavy rubber washer that came with the drain set. I had the same problem and solved it by removing the thick washer and using plumber's putty instead.