I've encountered two things that can cause this. The first is that SOSAM uses a different weight slider set in bodyslide than normal; it has a "weight 0 to 1" slider instead of "weight 1 to 0". You could've just set the wrong slider to 100. The second is just bodyslide being weird with mod organiser, if you haven't maybe try clearing and remaking your bodyslide output. It's probably not a runtime problem because modern SAM mods use racemenu for that
Actually it just occured to me that if you're using SOSAM you dont need to use the high poly conversion since i think it uses the high poly model anyway