diff --git a/Subsurface/Source/GUI/GUIComponent.cs b/Subsurface/Source/GUI/GUIComponent.cs
index 6b5730af5..8af57bd6c 100644
--- a/Subsurface/Source/GUI/GUIComponent.cs
+++ b/Subsurface/Source/GUI/GUIComponent.cs
@@ -461,6 +461,23 @@ namespace Barotrauma
 
         public virtual void AddChild(GUIComponent child)
         {
+            if (child == null) return;
+            if (child.IsParentOf(this))
+            {
+                DebugConsole.ThrowError("Tried to add the parent of a GUIComponent as a child.\n" + Environment.StackTrace);
+                return;
+            }
+            if (child == this)
+            {
+                DebugConsole.ThrowError("Tried to add a GUIComponent as its own child\n" + Environment.StackTrace);
+                return;
+            }
+            if (children.Contains(child))
+            {
+                DebugConsole.ThrowError("Tried to add a the same child twice to a GUIComponent" + Environment.StackTrace);
+                return;
+            }
+
             child.parent = this;
             child.UpdateDimensions(this);
 
diff --git a/Subsurface/Source/Physics/PhysicsBody.cs b/Subsurface/Source/Physics/PhysicsBody.cs
index ad1e881d9..3a4675a40 100644
--- a/Subsurface/Source/Physics/PhysicsBody.cs
+++ b/Subsurface/Source/Physics/PhysicsBody.cs
@@ -366,7 +366,15 @@ namespace Barotrauma
         
         public void MoveToPos(Vector2 pos, float force, Vector2? pullPos = null)
         {
-            if (pullPos==null) pullPos = body.Position;
+            if (pullPos == null) pullPos = body.Position;
+
+            if (!MathUtils.IsValid(pos))
+            {
+#if DEBUG
+                DebugConsole.ThrowError("Tried to move a physics body to an invalid position.\n" + Environment.StackTrace);
+#endif
+                return;
+            }
 
             Vector2 vel = body.LinearVelocity;
             Vector2 deltaPos = pos - (Vector2)pullPos;
@@ -502,11 +510,13 @@ namespace Barotrauma
                 //increase the interpolation speed to catch up with the server
                 float speedMultiplier = (float)Math.Pow(1.0f + (positionBuffer.Count - 2) / 10.0f, 2.0f);
 
-                netInterpolationState += (deltaTime * speedMultiplier) / (next.Timestamp - prev.Timestamp);
-                newPosition = Vector2.Lerp(prev.Position, next.Position, netInterpolationState);
+                float dT = next.Timestamp - prev.Timestamp;
+                
+                netInterpolationState += (deltaTime * speedMultiplier) / dT;
+                newPosition = Vector2.Lerp(prev.Position, next.Position, MathHelper.Clamp(netInterpolationState, 0.0f, 1.0f));
 
                 //override the targetMovement to make the character play the walking/running animation
-                newVelocity = (next.Position - prev.Position) / (next.Timestamp - prev.Timestamp);
+                newVelocity = (next.Position - prev.Position) / dT;
             }
             else
             {
@@ -514,6 +524,16 @@ namespace Barotrauma
                 netInterpolationState = 1.0f;
             }
 
+            if (!MathUtils.IsValid(newPosition))
+            {
+#if DEBUG
+                DebugConsole.ThrowError("Invalid physicsbody sync position "+newPosition);
+#endif
+                netInterpolationState = 0.0f;
+                positionBuffer.RemoveAt(0);
+                return;
+            }
+
             if (netInterpolationState >= 1.0f)
             {
                 netInterpolationState = 0.0f;