SA Framerate cuts in half at low altitude

[Findingpastorp]

https://drive.google.com/file/d/1CLLyAqNjmaxXXEV9TI_xNfZ4pYmoMB9p/view?usp=share_link

At the same altitude no matter what scene is being displayed my framerate cuts in half below around 800 ft. The attached link shows a more complex scene where the framerate starts around 120 and the instant the camera dips below that threshold it drops to 60 and goes right back up once the camera is back above that line. I've done the same experiment looking straight down at the ground and straight up at the sky, the results are the same every time, exactly half the framerate below a certain altitude. 

Another strange thing is that there have been short periods of time where the problem is not present, but during my testing its only about 10% of the time where it is not a problem and I can not seem to find the exact condition that causes it to start/stop. This has been very jarring during my time with this map, I can understand framerate drops in complex scenes but when it gets cut in half during regular flight over empty land that seems like there's a miss somewhere.

[PLUTON]

Hi known problem and report since the release of the SA maps, everyone hopes that Razbam will fix it as soon as they know where it comes from.
Patience and length of time etc; etc...