When you say “it is still clickable” are you referring to the buttons, or the video itself?
I could be mistaken, but I believe that even with the controllers turned off (set to None in Lectora) you can still toggle the play of the video by clicking it. Perhaps the pause/play buttons are hidden, but the toggle play is firing off of the video itself.?
Another possibility is that you’re selecting the wrong element with your CSS. Lectora tends to bury elements into many layers of nested HTML tags. For example, to use CSS to style an individual text field (perhaps the student made an entry error and you want to turn it lightpink) you can’t select it by the field’s HTML Name as assigned by Lectora. On publish, the HTML Name refers to the <div> surrounding the <input> field, rather than the field itself; the field’s <input> tag has a different id assigned to it. Sometimes you can select it by class instead, but that doesn’t always work. Perhaps, your display:none property is specifically selecting the image of the play button, but the <div> or tag above it is still displayed, so it’s still clickable.