diff --git a/rts/Sim/MoveTypes/MoveMath/MoveMath.cpp b/rts/Sim/MoveTypes/MoveMath/MoveMath.cpp
index 7d370644fc6..6603970a9df 100644
--- a/rts/Sim/MoveTypes/MoveMath/MoveMath.cpp
+++ b/rts/Sim/MoveTypes/MoveMath/MoveMath.cpp
@@ -135,7 +135,7 @@ CMoveMath::BlockType CMoveMath::IsBlockedNoSpeedModCheck(const MoveDef& moveDef,
 
 CMoveMath::BlockType CMoveMath::IsBlockedNoSpeedModCheckThreadUnsafe(const MoveDef& moveDef, int xSquare, int zSquare, const CSolidObject* collider)
 {
-	assert(Threading::IsMainThread());
+	assert(Threading::IsMainThread() || Threading::IsGameLoadThread());
 	return RangeIsBlocked(moveDef, xSquare - moveDef.xsizeh, xSquare + moveDef.xsizeh, zSquare - moveDef.zsizeh, zSquare + moveDef.zsizeh, collider);
 }