If they have no posts they are considered a new user, so until one of their queued posts is accepted all their posts will go to the post queue. If you are not using reputation make sure Reputation required to bypass post queue is set to 0 or lower.
@dunlix I'm already using a custom theme, but my site has it's own login system where the user is shown logged in at the top -- this would not be possible if i put it into a nodebb theme. Also session-sharing and iframe is already working perfectly.
@jim-bridger I too am making lots of changes in terms of CSS. What I do here is copy and paste to and from a full blown IDE on my desktop. This makes life much easier as it extends capabilities such as search etc.
I discovered this was due to the theme slick, which seemed to be broken to me, as the form and input elements were missing multiple values, which didn't get loaded when save was clicked, so no information was sent. I made a child theme to fix it.