Space

Personally I think the more complex pattern of having 3 different states being cycled through once an hour is significantly less likely to be natural.

That, of course, doesn't mean much by itself; it still is possible that it is natural and we just don't understand why. More research into how and why that is happening is absolutely required to answer the question. I just don't know if we will do it, or if we have the tech needed to fully investigate it yet.