http://bugs.winehq.org/show_bug.cgi?id=26714
--- Comment #4 from Jeff Cook jeff@deserettechnology.com 2011-06-27 03:29:26 CDT --- As mentioned in bug #24684, this only occurs if "Multicore Rendering" is enabled.
Nephyrin zey says: "Also broken with Multicore rendering are light aura occlusions (which valve have said is accomplished with last-frame occlusion queries)."
Disabling multicore remedies this problem on 1.3.23 for me.