I also use my T435 one-handed when limbing, but it's very unsafe, as it's impossible to control kickback with just one wrist. If you don't believe me, I have a scar in the midddle of my head to prove it. Thankfully my baseball hat and a quick trigger finger were enough to prevent more serious damage.
I still do it, but with much more care with what direction kickback could carry the saw, should it happen again. We all do our best to avoid contact with the deadly zone that is the upper quadrant of the bar tip, but when fighting through a mess of branches on a downed tree, these things can happen.