Index: source/maths/FixedVector2D.h
===================================================================
--- source/maths/FixedVector2D.h
+++ source/maths/FixedVector2D.h
@@ -204,6 +204,7 @@
 
 	/**
 	 * Compute the dot product of this vector with another.
+	 * Likely to overflow if both vectors are large-ish (around the 200 range).
 	 */
 	fixed Dot(const CFixedVector2D& v) const
 	{
Index: source/simulation2/components/CCmpUnitMotion.cpp
===================================================================
--- source/simulation2/components/CCmpUnitMotion.cpp
+++ source/simulation2/components/CCmpUnitMotion.cpp
@@ -1149,7 +1149,8 @@
 
 			// Check if we anticipate the target to go through us, in which case we shouldn't anticipate
 			// (or e.g. units fleeing might suddenly turn around towards their attacker).
-			if ((out - cmpPosition->GetPosition2D()).Dot(tempPos - cmpPosition->GetPosition2D()) >= fixed::Zero())
+			// To avoid overflows, divide both vectors by 1000 since only the sign matters.
+			if (((out - cmpPosition->GetPosition2D()) / 1000).Dot((tempPos - cmpPosition->GetPosition2D())/1000) >= fixed::Zero())
 				out = tempPos;
 		}
 	}