Thanks for the report. A member of the Infinite Flight Airport Editing Team might look into it and could perhaps fix it!
This issue has been reported several times.
It’s something the IFAET can’t fix.
This could be fixed by IF-AET. The airport elevation is already correct (10’). Simply expand the airport boundary to include the areas where the digital elevation model is wrong. This will create a landscape that is much closer to reality than now. It will make the head of the fjord almost sea level rather than hills, and the valley floor flat and low elevation, which is quite close to the way it is in reality.
The DEM is wrong because the Shuttle Radar Topography Mission (used by IF I believe) couldn’t see into this incredibly steep and spectacular fjord, so the SRTM data set guessed at elevations where it couldn’t see, and guessed wrong.