*wipes sweat from forehead in preparation*
OBS can't actually directly cause a hard lock of the computer. Typically if your computer is hard locking then it could be faulty hardware, poor overclock, or overheating. (or really really bad drivers, but it's very rare for drivers to do that)
Streaming is fairly CPU/GPU intensive when combined with gaming, so you will be more likely to experience latent instabilities when streaming than when not. You're encoding, gaming, and capturing video all at the same time, so you're using a lot of your system power to do so, so you will be more likely to experience any existing (again, existing) instabilities while streaming and gaming than any other activity.