After the pause the sim keeps running incredibly good and no stuttering at all but I believe that a 10 second loading pause should not be right.
That's exactly what is supposed to be happening, if you set the anti pop-up to the maximum slider. The anti pop-up is not a "magic" slider that will remove stuttering. It's just a tool that let you select WHEN objects are loaded.
If is set to it's default value, objects are loaded at the distance WE set in the scenery so, some of them will load early, some of them will load later so, instead of a large pause, you might (or might not, depending how your system is under heavy load) have several very small pauses.
By setting it to high values, everything will be loaded at the maximum scenery range ( 16.0 NM ) so, instead of many small pauses, you'll get a single, big pause.
Most users will prefer a single, large, pause when you are farther away, instead of smaller pauses when you are on final, but of course, if you don't like the single, big, pause, you can put the setting back to the default of 1.
Now the obvious answer to the usual question: "this issue does not happen with any other addon airports". That's a FEATURE of the scenery, of course, not a bug. It means WE do memory management, and YOU can also control it.
Other airports are in the hands of the FSX memory management, so they don't have any control over it. That doesn't mean FSX doesn't load the scenery but, it does it very slowly, in the background, and it starts loading it when you are WAY more distant.
This, of course, is not "free" (there's no free lunch, as they say), because the added cost of this very slow and progressive loading starting from a larger distance, is that other addons airports will take memory even when you are much farther away, sometimes even if you are just flying around and don't really need to go to that airport. Of course, something like this, in an area when there are several large airports together, like the New York area for example, it's a disaster for your memory consumption, and with all the memory-hungry airports out there, and all the different addons installed together, the risk of OOMs is way higher.
WHICH IS WHY, other developers are forced to create "configurators", since they know that, without the memory management, that we do in a totally custom way, there's no way their scenery would fit with everything at the same time. Which are quite cumbersome, since they always require to exit the sim, re-configure, re-launch, test again, only to realize that, a large detailed airport that doesn't use our memory management, will never fit in memory together with the most complex airplanes with all the options enabled.
So, those pauses are your friends. They enable to enjoy a detailed scenery, without cumbersome configuration options, and with a very low risk of OOMs.