http://bugs.winehq.org/show_bug.cgi?id=58216
--- Comment #7 from yshuiv7@gmail.com --- There is a recent use-after-free fix in winegstreamer that has gotten into 10.15 so I thought that might be it :(
And this is really weird. I am tried old-WoW and 32-bit, both works. The video still does play but I can even hear its audio playing. After that, the game starts. I wonder what's different between your setup and mine.