Attempt to fix a rare yet critical crash

src/fos/core/FOSMod.java

@@ -22,6 +22,7 @@
 import fos.ui.*;
 import fos.ui.menus.*;
 import mindustry.ai.Pathfinder;
+import mindustry.core.GameState;
 import mindustry.game.*;
 import mindustry.gen.*;
 import mindustry.mod.Mod;
@@ -157,6 +158,10 @@ public void init() {
                 Reflect.invoke(pathfinder, "preloadPath", new Object[]{pt}, Pathfinder.Flowfield.class);
             }
         });
+        Events.on(EventType.StateChangeEvent.class, e -> {
+            // reset the flowfield's vector on exit.
+            if (e.to == GameState.State.menu) FOSVars.fposVector.setZero();
+        });
 
         //anything after this should not be initialized on dedicated servers.
         if (headless) return;

src/fos/core/FOSVars.java

@@ -32,8 +32,10 @@ public class FOSVars {
     /** Capsules creator **/
     public static CapsulesController capsulesController;
 
+    /** Internal. */
+    public static Vec2 fposVector = new Vec2();
     /** A flowfield used in certain custom AIs. */
-    public static Pathfinder.Flowfield fpos = new Pathfinder.PositionTarget(new Vec2());
+    public static Pathfinder.Flowfield fpos = new Pathfinder.PositionTarget(fposVector);
 
     /** Enabling debug mode debug **/
     public static final boolean debug = Core.settings.getBool("fos-debugmode");