*facepalm*

common/src/main/java/us/myles/ViaVersion/protocols/protocol1_13to1_12_2/Protocol1_13To1_12_2.java

@@ -840,7 +840,7 @@ public class Protocol1_13To1_12_2 extends Protocol {
     }
 
     private int getNewSoundID(final int oldID) {
-        return MappingData.blockMappings.getNewBlock(oldID);
+        return MappingData.soundMappings.getNewSound(oldID);
     }
 
     // Based on method from https://github.com/Bukkit/Bukkit/blob/master/src/main/java/org/bukkit/ChatColor.java