High resolution heightmaps not working anymore

Hmm… to put some more context to it:
Ignore my latest comment about the chairs, they just don’t have the legs, which is an LOD, not an elevation related issue as mentioned here:

After some further observation I believe that heightmaps ARE either being loaded as before or not at all. What however I do not understand yet why some are loaded, others are not:

Aerosoft EGAR Rothera with heightmap loaded and terrain bugfixing. Looks good:

Aerosoft YWKS Casey helipad area with terrain bugfixing active but heightmap not rendered: