I considered that a backwards compatibility breakage and also a bug and I don't know what to do now. Purr Data's version also introduced "smmf" mode and I was keeping it all just so an external or a patch from Purr Data that uses fluid~ could run in Pd Vanilla, but I don't feel like keeping this bug/breakage. So I can ask them to fix it over there or just fix the bug and remove "smmf" mode and compatibility to Purr Data.