Checked it on my PC with all installed that ORBX offers for that area. Got no flying buildings at Merill field.
Flying objects are caused by an "timing loading error", when the autogen objects are placed while a low LOD mesh (or a flatten file not yet) is loaded. They keep their height. When the sim engine switches to a higher mesh LOD level (which could be lower due to its higher resolution at some areas) autogen buildings are flying. I don´t know any other possible reason. It often happens while slewing around (which you didn´t), but can also happen at dense areas.
Since FTX SAK is a very dense area it could possibly happen that the timing of loading things like mesh and autogen went wrong. But as Oliver allready wrote: Nothing of our files affects that area around Merill Field.

To test it: Save the flight and load it again. Than the loading or timing order is correct and everything should look fine.