Could be any number of things. Could just be that you are very chest dominant (as opposed to shoulder and/or tri) on bench. Could be lack of stability when doing press while standing. Could be weak external rotators or flexibility issue in your shoulder. Form perhaps?
Ever tried behind-the-neck presses instead?
Your OHP is definitely low compared to your bench though, just a tad over 50% from the looks of it. A more standard ratio is something around 65% I'd say, at least for people who train both lifts. And then people doing 70%+ are probably pretty shoulder dominant. Though from what you said above, not sure that you really consistently train it, so it could also be that.