Dear Chris
The problem is happening with all input file, even with the sample input file. I am using native Ubuntu installation. I have tried with command SLOWAA=yes, but the problem persists. What I have found is that my PC being old one is having Core2 duo processor and the “geoviewer” crashes with any version of linux. I have tried with fedora32, ubuntu 18.04 and Ubuntu 20.04. In new machines starting from i3 processors, the problem goes away. This is my personal view, may be I am wrong.
With regards,
Sujoy Chatterjee