I've noticed too a couple times after i just started it while backing out in the dark thinking it was a little oil or something on the engine burning off but the other day, wow. After washing nitro and spraying thru rad fins to remove bugs and letting dry. A few hrs later on a midnite run, did I ever see steam coming out the front end. It was actually condensating too but it being nite time i couldn't see where it was actually escaping because the wiper reservoirs are in the damn way

I'LL REPOST WHEN I SEE ROOT CAUSE and all levels of coolants appear normal.