Found a workaround. Uninstalling IncrediBuild (which is part of the VS2017 C++ developer tools) brings shader compiling and recalculating lights back to life. Thanks to the answer in a separate thread for this workaround.
However, I’d like to continue using IncrediBuild for other use work. Is there a way to make Unreal 4.19 work with IncrediBuild installed?
Thanks!