No, it never worked. For DTS-HD MA anyway. It works fine for TrueHD. And it works fine for DTS-HD MA MKV's made with MakeMKV. I can't get Haali to split DTS-HD MA m2ts/ts files so I can't test that.
Honestly, at this point, I'd be SUPER FREAKING PSYCHED if the MPC splitter was updated to handle PGS subs in MKV's. I'm seriously.