I've been looking around in the bug reports and I thought I saw this somewhere, but can't find it again.
Basically, I started a game and picked up research labs early on. I never built a basic research facility. However, no matter how many labs I built, my planetary research never went above 3 points. (well, it would get to 5, if I adjusted my economic spending slider to ~80% research). I've got planets with three and four labs, but...
In the next game, I built basic facilities and upgraded them. I don't think my planetary research dropped any, but I can't say that it improved, either.