This may be caused by the listing of some exchanges, which led to the excessive circulation of Ethereum and some tokens during a certain period of time. They need to transfer tokens to these exchanges to get a chance to vote.
I don't believe now on Ethereum exchange they had numerous problem if you going to look on their wallet it's all congested. I don't what will Vitalik will do in his project. This is extremely exhausted! hope they can fix it