I'm using Build 838 and it still hasn't fixed this issue, which is quite annoying for me, while foobar does read Replaygain tags correctly in WavPack files. I even tried to make Poweramp read the files with ID3v1+APEv2 tags but it didn't work either.
It seems that for the developers the Replaygain issues are low priority, which shouldn't be so because I'm sure for those of us who use it is a decicive feature for a music player.
I hope this old problem will be solved in the next versions. In the meantime, I will continue to use foobar.