reason given on another discussion (this one private) is that any code based on the public sources counts as derivate work under GPL3, and as such it cannot be imported into Rack Pro (which includes fundamental),
it is a self-made problem though, and really sucks that it becomes impossible to create a community around the core codebase.
This reminded me of a problem that I ran into a while ago, which @carbon14 traced to this bug in nanovg. I worked around the issue by disabling antialiasing on some of my lights. I didn’t realize that I’d caught this other VCA bug in the mix as well.