Most of the red zone around Moscow is situated on east and northeast, whereas "oligarch dachas" are mostly located directly west of Moscow (that hexagon is also red).

I think it's mostly aerospace installations apparent on that map, such as https://ru.wikipedia.org/wiki/Медвежьи_Озёра_(центр_космичес...

Not sure what's going on in Pereslavl-Zalessky.

Having said that, of course GPS/GLONASS in the form of consumer phone-based navigation works just OK in Moscow. There is sometimes visible interference near the Kremlin though (your phone might suddently think it's in VKO).