As the title says, is there a SE site which lets people ask about technical bugs / problems about video games? Made-up example, I found a bug where you can die randomly while flying in Minecraft.
As Shadow Wizard said in a comment above, Arqade does sometimes deal with this sort of thing ("Game-specific hardware and utilities" is the most relevant on-topic listing there).
But in general, I'm not sure what you're describing is really appropriate for the Stack Exchange network. It really just depends on what you're hoping to find out.
If you post the "question," "hey guys! I found a bug! Isn't this awesome?" you probably won't be well-received, and the very best-case answer will be something along the lines of "yep! I'm reproing that, too." If you're certain that what you've found is actually a bug in the software, your best bet would be to go to the manufacturer and report it via whatever means they have set up, if any.
On the other hand, if your question is more along the lines of "[this weird thing] is happening under [these specifically laid out circumstances], is this a bug? And is there a known work-around if so?" that's probably more suitable. Of course, that could also be prone to a self-answer, if you find a bug and want to post your solution.
But, just like with Stack Overflow, remember that sites in the Stack Exchange network aren't a direct link to developers of specific software, and consequently shouldn't be used for bug reporting (except for bugs about Stack Exchange itself) or other customer service requests. Arqade is probably your best bet, but just make sure that you're actually asking a question when you go there.
It might not be a bad idea to hop on their chat and see whether people think it would be a good thing to post on the main site. I'm not immediately familiar with their practical scope, and anyone there probably will be. They might also be able to help you assess whether it's reproducible, which could be good to know going into asking your question.