I had the same problem, and when I found this thread I spent some time trying to make sense of the proposed solutions. However, the problem has been solved in recent updates, as far as I can tell, with some changes to the "effect_freeverb.cpp" file specifically. So if anyone is still banging their head against this, you just need to update your software. I just swapped out the one file, and now freeverb works great in my project.