sorry completely misread your post. I'll leave that bit there incase anyone had that problem.
I dont know what the problem would be if it still closes after one session when you use -L

try it on your own computer and telnet to it, close it and telnet again. See if it works on yours.
I havent had any times myself when it hasn't restarted when i've used -L so I'm stumped

edit/ the only temporary solution I can think of for it is if you just start another nc session on a different port before you disconnect. Not the best solution but it's better than no solution