I too have the same problem. 16GB RAM, SSD, i7-4770K, GTX 980 - no other issues, just this, and it occurs randomly, but usually past turn 100. Zooming in/out repeatedly is the quickest way to reproduce.
Occurs with/without autosave
Occurs on all galaxy sizes
Occurs with/without Steam Community Overlay
Edit: I'm encountering the same issue on an Ultrabook with 8GB RAM, SSD, i7-4650U, Intel HD 5000.