Fixed #4121

core/src/mindustry/io/TypeIO.java

@@ -317,7 +317,11 @@ public class TypeIO{
             return player;
         }else if(type == 1){ //formation controller
             int id = read.i();
-            return prev instanceof FormationAI ? prev : new FormationAI(Groups.unit.getByID(id), null);
+            if(prev instanceof FormationAI f){
+                f.leader = Groups.unit.getByID(id);
+                return f;
+            }
+            return new FormationAI(Groups.unit.getByID(id), null);
         }else if(type == 3){
             int pos = read.i();
             if(prev instanceof LogicAI pai){

core/src/mindustry/world/blocks/power/NuclearReactor.java

@@ -100,7 +100,7 @@ public class NuclearReactor extends PowerGenerator{
                 float smoke = 1.0f + (heat - smokeThreshold) / (1f - smokeThreshold); //ranges from 1.0 to 2.0
                 if(Mathf.chance(smoke / 20.0 * delta())){
                     Fx.reactorsmoke.at(x + Mathf.range(size * tilesize / 2f),
-                    y + Mathf.random(size * tilesize / 2f));
+                    y + Mathf.range(size * tilesize / 2f));
                 }
             }