diff --git a/src/p_setup.c b/src/p_setup.c
index 50b073a213c6fcd359f0fc53a621f726fcd5a1a4..61d1a5e461b37bcb3c3fd086ad99ab5a8d720e2c 100644
--- a/src/p_setup.c
+++ b/src/p_setup.c
@@ -2998,7 +2998,7 @@ static void P_AddBinaryMapTags(void)
 				boolean matches_target_tag = Tag_Find(&sectors[j].tags, target_tag);
 				size_t k; for (k = 0; k < 4; k++) {
 					if (lines[i].flags & ML_EFFECT5) {
-						if (matches_target_tag || offset_tags[k] && Tag_Find(&sectors[j].tags, offset_tags[k])) {
+						if (matches_target_tag || (offset_tags[k] && Tag_Find(&sectors[j].tags, offset_tags[k]))) {
 							Tag_Add(&sectors[j].tags, tag);
 							break;
 						}