Hi.
If you save a project with the “Terrain Height Scale” (THS) setting to 4000m for example, when you reload that project, the THS indicate 2520 (the default value) but the landscape is generated with the saved vallue (4000). If you slightly move the THS then the terrain now have the new value (for example with a slightly move on the Right : 2640).
So I think the problem is that when you load a project, the THS display is simply not updated with the value in the project file.