I don't use WeChat, but I have looked into it. Some of my research is working on that direction of disinformation.
We see that during election times, some of the WeChat groups are very active. Many WeChat groups are just ordinary WeChat groups. They talk about going to dinner, going to a barbeque or other leisure activities. During election times, sometimes a different group of people will emerge and start talking about, promoting or going against specific candidates. That's what we have observed in the group.