Summary: This one was mentioned before, but I thought it would be good to have a separate topic for it. Sometimes when transitioning from day to night (and perhaps also from night to day?), you get a brief flash of light. Not sure why it happens sometimes and not other times.
Versions and mods: No mods, latest release version in Steam at the time of writing, version 0.1.0 (release 122) according to the title screen.
OS: Windows 8 Pro 64 bits (6.2, build 9200)
Processor: Intel® Core™ i5-3450 CPU @ 3.10GHz (4 CPUs), ~3.5GHz
Memory: 8192MB RAM
DirectX-version: DirectX 11
Graphics card: NVIDIA GeForce GTX 660