diff --git a/src/p_map.c b/src/p_map.c
index da8e5463a..39a4c1d86 100644
--- a/src/p_map.c
+++ b/src/p_map.c
@@ -1628,6 +1628,13 @@ static BlockItReturn_t PIT_CheckLine(line_t *ld)
 		g_tm.blocking = true;
 		return BMIT_CONTINUE;
 	}
+	else
+	{
+		if (g_tm.sweep)
+		{
+			P_TestLine(ld);
+		}
+	}
 
 	if (P_IsLineBlocking(ld, g_tm.thing))
 	{