Hello,
I am having this strange behavior when using the Reflection override with the newest daily build.
When I don't use an override I get a normal-looking material but as soon as I turn it on I get these little specs all over. I thought it was the material at first but it was not.
Tried it with a plain material same thing. I am using an HDRi plugged into a corona color correct but the values of both maps are exactly the same.