Google analytics is showing WECHAT_EMPTY_TITLE as a Page Title in Behaviour --> All pages report for few pages for website even page title is totally different in those pages which we can look at with view-source.
Did anyone recently see this behavior in google analytics?
Here's a very late response since I ran into this myself at work and there are no other sources about this issue. I'm not actually a dev so if anyone can complete this answer with more technical details (if needed), that would be helpful.
Are you returning the 404 status code when a webpage is not found within your domain? If you return 200 and redirect to a friendly "not found" page, Analytics will record it as a regular page access within your domain.
Chances are someone accidentally managed to access yourwebsite.com/WECHAT_EMPTY_TITLE and analytics tracked it because it was deemed a successful request. This was our problem and it went away once we started returning 404 instead.