I do see where this was broken in 4.12.x with Skylights as well for translucent materials compared to 4.11.2, When I checked my sample project that I made with 4.11.2 with our internal build of 4.13 this looks to be resolved already.
Currently, there are no additional hotfixes that I’m aware of for 4.12 so this shouldn’t be an issue once 4.13 is released towards the end of August or Early September. The previews should be starting a little bit before then for testing purposes.