I had the same observation and my suspicion after some tests was confirmed by the 3rd party developer “Bijan” in this forum:
Photogrammetry trees are usually perceived as ugly, especially in old photogrammetry data like in Nuremberg. Dedicated 3D models look nicer and blend better with the landscape having no photogrammetry. Thus Asobo does the trick of hiding the photogrammetry trees beneath 3D models which are modified so they always show in the foreground. In order to more or less completely hide the PG tree blobs the 3D models must (a) be larger than the tree to be hidden and (b) they must be evergreen for the camouflage to work all year round.
The result is oversized 3D evergreen tree models in many photogrammetry cities like Nuremberg, Berlin, Vancouver, Paris etc.
Thus I am sure this is by design, and it’s the lesser evil they chose.
If you purchase Bijan’s “Seasons Enhanced” addon (for FS2024) and remove the files for the photogrammmetry exclusion polygons then you will see what happens otherwise: With his correctly sized trees you will see the photogrammetry PG tree blobs within the tree models and it looks equally poor… just a different type of poor, so to say.
Now, can this get fixed?
Just imagine trees (e.g. conifers) standing in close to the front of buildings so that you cannot see the facade behind. It’s simply impossible to get a photo of the facade from the air without the trees, agreed?
Since even newer photogrammetry models with better quality cannot get completely rid of the trees without removing parts of the buildings behind them, this is almost a “Won’t fix” issue. I say “almost” because as technology advances it might become feasible to use some (maybe AI-powered) algorithms to detect and get rid of the trees in the 3D mesh anyways and then fill in the created gaps in the facades behind and the ground below with “something plausible”, then place (only) the 3D tree model over it and maybe if the 3D tree hides the correction well enough then you might not notice it until looking very closely.
I hope I could explain this well enough.