Well, my Inspector seems to be broken right now. Can't change any settings
Here's where mine differs (might help)
Antialiasing - Setting = 16x[16x CSAA (4 color + 12 cv samples)]
Antialiasing - Transparency Supersampling = 8x Sparse Grid Supersampling
Anistropic Filtering Mode = Although I know it should be at User Defined/Off, mine is at Application controlled
Anistropic Filtering Setting = 16x
Also, in FSX:
Filtering = Anistropic
Anti-Aliasing = Unchecked
Hmm...FSX looks better than I remember (haven't flown it in a while), mainly went back to FS2004
Don't fly the PMDG but, haven't seen your issue on any of my aircraft (default, iFly, Level-D and various Feelthere/Wilco).
Remembering your settings, just in case, give mine a shot and see if they help.