Substance Model graphs and their result in the 3D View in real time are very intensive to calculate, which can lead to instability on some systems. These graphs are calculated on the CPU exclusively and systems with mobile-grade hardware with lower power limits can run into issues.
If you are prompted to send a bug report on the next start of Substance 3D Designer following a crash, please consider doing so. It send us more detailed information about the specific processes which crashed, which helps us narrow down the specific issue.
Also, please note this is the first version of a large and technically challenging feature which we will grow and improve over time. I appreciate your patience during this process.