diff --git a/src/p_mobj.c b/src/p_mobj.c
index b5c83468a..88c269b26 100644
--- a/src/p_mobj.c
+++ b/src/p_mobj.c
@@ -7800,6 +7800,9 @@ static void P_MobjSceneryThink(mobj_t *mobj)
 			mobj->z = mobj->target->z + mobj->target->height + FixedMul((16 + abs((signed)(leveltime % TICRATE) - TICRATE/2))*FRACUNIT, mobj->target->scale);
 		else
 			mobj->z = mobj->target->z - FixedMul((16 + abs((signed)(leveltime % TICRATE) - TICRATE/2))*FRACUNIT, mobj->target->scale) - mobj->height;
+
+		mobj->old_z = mobj->z;
+
 		break;
 	case MT_LOCKONINF:
 		if (!(mobj->flags2 & MF2_STRONGBOX))
@@ -7811,6 +7814,9 @@ static void P_MobjSceneryThink(mobj_t *mobj)
 			mobj->z = mobj->threshold + FixedMul((16 + abs((signed)(leveltime % TICRATE) - TICRATE/2))*FRACUNIT, mobj->scale);
 		else
 			mobj->z = mobj->threshold - FixedMul((16 + abs((signed)(leveltime % TICRATE) - TICRATE/2))*FRACUNIT, mobj->scale);
+
+		mobj->old_z = mobj->z;
+
 		break;
 	case MT_DROWNNUMBERS:
 		if (!P_DrownNumbersSceneryThink(mobj))