For sure it will be caused by some kind of noise on the powerline, whether it's a control signal (ripple signal) or something else I don't know, but in my case the flashing occurs multiple times per hour. Anyway, I was on 1.7.6 and 1.8.0, as of today on 1.8.2, we'll see if that brings luck.
It can't be the bulbs (both halogen 50W and Ikea and Philips LED bulbs have it).
The fact that not many people seem to have the issue is not relevant nor is it a reason not to solve this asap; you need a 75pct happy customers to build and keep a good reputation, but only 5pct of unhappy customers for a bad one. To be clear: I'm with the 75pct unless this issue doesn't get solved