I am having the same problem as well. I installed the scenery through P3DV4 scenery installer and the LFML_ADEX_TLG_ALT.BG is in the scenery\world\scenery folder. I moved the main scenery folder to the top of the list and still have the same problem.
I have removed every file in the LFMLscenery file and put them back in a few at a time and I found that the "Marseil_ground_flatten.BGL" file might be the cause. When it is removed everything is fine except the airport is at 85 feet altitude instead if around 8 feet which is about what it is suppose to be.
Any more help in this would by great.