I noticed something very similar a few days ago but instead of what you mentioned EVERY vote was for MN 1000 and MN and POW so it's not all one way.
First of all I voted myself and asked relatives and friends choose Not PoS+MN & Not 10 000 GOA & 20 GOA. And I noticed what every time voting results diverge from some value somebody adds few votes to PoS+MN.
I wondered and, as I said, I have 89 colleagues, so at Thursday I asked them vote for PoW+MN & 1000 GOA & 20 GOA. At the beginnig they responded sluggishly but I was persistent. At Friday almost all voted. It was real people and votes went for all day.
But votes for PoS+MN & 10 000 GOA & 10 GOA goes by 50 per 15 minutes. It's nonsense and 100% cheat with bots.