[tor-relays] Tor not releasing port on shutdown?

Hi, the most recent times I have tried to restart Tor after a 'killall -INT' I have been presented with the following error: "[warn] Could not bind to 0.0.0.0:9001: Address already in use. Is Tor already running?" I'm not sure if this has started since I changed version, I'm on Tor 0.2.2.22-alpha (git-e5e38e55b33b2cc0) OSX 10.3.9 . Anyone else see this? How do I release that port? Command 'lsof -i' returns no results, so I don't see Tor is really using it still - no sign of Tor in command 'ps -aux' output.

Update: after running those commands, Tor was able to start. Why the delay? Is this normal?

TIA GD