Hi, Rina,
Well, I think you cannot go wrong with such an simple stroller maintenance activity as lubricating it. I mean, many prams and pushchairs, even the Cybex MIos 2 models, for example, are not lubricated enough right out of the box. So yeah, do try and oil the joints that get stuck (start gently) then fold and unfold the stroller at least 4-5 times.
It can also be the newness of the stroller where the joints are a bit harder and stiffer at the start. I would try for the next few days, after lubrication, to fold it regularly. If after those days (maximum a week) there are still problems, it will be an internal problem which I would take to the shop/the seller of the stroller, ideally showing him the problem live, but if this is impossible, sending him a video uploaded on YouTube as proof. It is always better to see the problem than just talk about it, and he might have a better answer or an update right from the manufacturer, Stokke.