diff --git a/mysql-test/main/group_min_max.result b/mysql-test/main/group_min_max.result
index 452088f358b..b0155f4fd85 100644
--- a/mysql-test/main/group_min_max.result
+++ b/mysql-test/main/group_min_max.result
@@ -4349,3 +4349,15 @@ drop table t1;
 #
 # End of 10.6 tests
 #
+#
+# MDEV-36118 Wrong result in loose index scan
+#
+CREATE TABLE t1 (a int, b int, KEY (a, b));
+insert into t1 values (1, 3), (1, 1);
+SELECT MAX(b) FROM t1 WHERE (b > 2 AND b < 4) OR (b = 5) GROUP BY a;
+MAX(b)
+3
+drop table t1;
+#
+# End of 10.11 tests
+#
diff --git a/mysql-test/main/group_min_max.test b/mysql-test/main/group_min_max.test
index 7f974aa61e6..d3aae2e2321 100644
--- a/mysql-test/main/group_min_max.test
+++ b/mysql-test/main/group_min_max.test
@@ -2007,3 +2007,29 @@ drop table t1;
 --echo #
 --echo # End of 10.6 tests
 --echo #
+
+--echo #
+--echo # MDEV-36118 Wrong result in loose index scan
+--echo #
+
+CREATE TABLE t1 (a int, b int, KEY (a, b));
+insert into t1 values (1, 3), (1, 1);
+--source include/maybe_debug.inc
+if ($have_debug) {
+  --disable_query_log
+  set @old_debug=@@debug;
+  set debug="+d,force_group_by";
+  --enable_query_log
+}
+SELECT MAX(b) FROM t1 WHERE (b > 2 AND b < 4) OR (b = 5) GROUP BY a;
+if ($have_debug) {
+  --disable_query_log
+  set debug=@old_debug;
+  --enable_query_log
+}
+
+drop table t1;
+
+--echo #
+--echo # End of 10.11 tests
+--echo #
diff --git a/sql/opt_range.cc b/sql/opt_range.cc
index d649926abf7..6985f43a623 100644
--- a/sql/opt_range.cc
+++ b/sql/opt_range.cc
@@ -16090,7 +16090,7 @@ int QUICK_GROUP_MIN_MAX_SELECT::next_max_in_range()
   ha_rkey_function find_flag;
   key_part_map keypart_map;
   QUICK_RANGE *cur_range;
-  int result;
+  int result= HA_ERR_KEY_NOT_FOUND;
 
   DBUG_ASSERT(min_max_ranges.elements > 0);
 
@@ -16099,10 +16099,11 @@ int QUICK_GROUP_MIN_MAX_SELECT::next_max_in_range()
     get_dynamic(&min_max_ranges, (uchar*)&cur_range, range_idx - 1);
 
     /*
-      If the current value for the min/max argument is smaller than the left
-      boundary of cur_range, there is no need to check this range.
+      If the key has already been "moved" by a successful call to
+      ha_index_read_map, and the current value for the max argument
+      comes before the range, there is no need to check this range.
     */
-    if (range_idx != min_max_ranges.elements &&
+    if (!result &&
         !(cur_range->flag & NO_MIN_RANGE) &&
         (key_cmp(min_max_arg_part, (const uchar*) cur_range->min_key,
                  min_max_arg_len) == -1))