That is interesting. My stock airport (MS2020) behaves perfectly; all my other base sims and addons that I have in the area. (EGHE, EGHQ, EGTP and EGTE) are also faultless.
Aerosoft and I have spent weeks loading and loading addons and testing different settings but to no avail.
I spoke too soon - Aerosoft Perranporth (EGTP) has now become infected with the same elevation problem as Land’s End - it is like a roller coaster. I have disabled the Communities folder by renaming it (which contains a few Twin Otter liveries and West Country airports and scenery enhancements) but with no effect.
Do you know if simply disabling the Communities folder is as good as uninstalling the addons contained therein? Is it possible that some 3rd party (elevation) data could have found its way into MSFS files which would cause the problem?
If the community folder is gone, the UK update Lands End isn’t installed in the content manager, and the contagion is spreading then that’s extra mysterious.
I don’t see how third party elevations can affect anything if there’s no third party content any more.
I will persevere with my testing and report back - I am more familiar with MSFS and the User files these days - so I can be a little more probing than my testing earlier in the year.