Is it? It doesn't sound correct to me. "There is 1 blue dot and 1 green dot" certainly sounds more correct. Whereas "There are 3 blue dots and 1 green dot." also sounds correct.

Either way, it doesn't matter because both of these items can't be in the same sentence, they must be broken up into two distinct strings to make it possible for translators to handle and for us to automatically substitute. From now on a unique string can only have a single usage plural usage in it.