I can confirm this problem and would like to quote one of my issues which I posted on a different forum:
Three times flying from GCTS to LSGG on BELUS arrival route, three CTD somewhere between CBY and GVA VOR's.
Name der fehlerhaften Anwendung: Prepar3D.exe, Version: 5.1.12.26829, Zeitstempel: 0x5fb44f72
Name des fehlerhaften Moduls: terrain.dll, Version: 5.1.12.26829, Zeitstempel: 0x5fb44edf
Ausnahmecode: 0xc0000005
Fehleroffset: 0x0000000000009313
ID des fehlerhaften Prozesses: 0x27ec
Startzeit der fehlerhaften Anwendung: 0x01d6ed63861d271e
Pfad der fehlerhaften Anwendung: D:\P3Dv51\Prepar3D.exe
Pfad des fehlerhaften Moduls: D:\P3Dv51\terrain.dll
Berichtskennung: 646295e9-957e-4c59-8491-8f00e850fe59
Vollständiger Name des fehlerhaften Pakets:
Anwendungs-ID, die relativ zum fehlerhaften Paket ist:
I also had a CTD when flying over/past Geneva during a flight from Zürich to Malaga.
I tried LSGG from two publishers, Aerosoft and FSDT. Both had the same issues. I have uninstalled LSGG and don't fly there anymore due to the issues
Im on P3D v5.1 latest version (HF1)