I've simplified the material so it has only a diffuse color and a bit of reflection.. no masks no translucency, refraction... And I tried several different render settings nothing makes it go away. They're less prominent if I use low sky and sun intensity values but still appear here and there plus the longer the render goes the more of them seem to appear. Turning image filtering off makes them smaller turning it on with default values(cone 1,5 + internal res 2) makes less of them appear but they're bigger :D....
So either I'm doing something very wrong. Or there is a problem with reflection and lots of dense geometry...
Btw can't run assert version of corona(max will crash, not able to load plugins)