oh, it is the recently updated 1.3 of the Rotate MD-80, so this is what I have. The HD Mesh thing, yeah well, that was a temporary solution I already should have fixed with the new tiles LR brought out with PB14. Forgot to get rid of them. But it was on a flight from KMEM to KATL so there was no HD Mesh active for that area, not even close (lots of distance to 60°N and beyond) - but I am going to take care of it, as well with the 2K textures for the MD80, which have been released a couple of hrs ago. So it is most likely a memory issue which can be fixed on various ways.
Thanks a lot for your help.