diff --git a/src/newgrf_optimiser.cpp b/src/newgrf_optimiser.cpp
index b4700f3007..d51d216367 100644
--- a/src/newgrf_optimiser.cpp
+++ b/src/newgrf_optimiser.cpp
@@ -1856,7 +1856,7 @@ static bool CheckDeterministicSpriteGroupOutputVarBits(const DeterministicSprite
 			/* Unpredictable load */
 			bits.set();
 		}
-		if (adjust.variable == 0x7D && adjust.parameter) {
+		if (adjust.variable == 0x7D) {
 			bits.set(adjust.parameter & 0xFF, true);
 		}
 		if (adjust.variable == 0x7E) {