fix: handle backend issue list regressions

server/store/group_message_runtime.go

@@ -1411,7 +1411,8 @@ func (r *redisGroupMessageRuntime) hotSeqIDs(tenantID types.TenantID, topic stri
 	if err != nil {
 		return nil, false, err
 	}
-	if len(raw) < limit {
+	expected := hotSeqExpectedCount(opts, limit)
+	if len(raw) < expected {
 		return nil, false, nil
 	}
 	seqs := make([]int64, 0, len(raw))
@@ -1425,6 +1426,23 @@ func (r *redisGroupMessageRuntime) hotSeqIDs(tenantID types.TenantID, topic stri
 	return seqs, true, nil
 }
 
+func hotSeqExpectedCount(opts *types.QueryOpt, limit int) int {
+	if limit <= 0 {
+		return 0
+	}
+	if opts == nil || opts.Since <= 0 || opts.Before <= opts.Since {
+		return limit
+	}
+	expected := opts.Before - opts.Since
+	if expected <= 0 {
+		return limit
+	}
+	if expected > int64(limit) {
+		return limit
+	}
+	return int(expected)
+}
+
 func expandRanges(ranges []types.Range, limit int) []int64 {
 	if limit <= 0 {
 		return nil

server/store/group_message_runtime_test.go

@@ -488,6 +488,21 @@ func TestTopicAndSubscriptionCacheTTLIsShort(t *testing.T) {
 	}
 }
 
+func TestHotSeqExpectedCountUsesRangeSizeWhenSmallerThanLimit(t *testing.T) {
+	if got := hotSeqExpectedCount(&types.QueryOpt{Since: 41, Before: 54, Limit: 20}, 20); got != 13 {
+		t.Fatalf("expected range-sized count, got %d", got)
+	}
+	if got := hotSeqExpectedCount(&types.QueryOpt{Since: 41, Before: 80, Limit: 20}, 20); got != 20 {
+		t.Fatalf("expected limit-sized count, got %d", got)
+	}
+	if got := hotSeqExpectedCount(&types.QueryOpt{Since: 0, Before: 54, Limit: 20}, 20); got != 20 {
+		t.Fatalf("expected fallback limit count, got %d", got)
+	}
+	if got := hotSeqExpectedCount(nil, 20); got != 20 {
+		t.Fatalf("expected nil opts limit count, got %d", got)
+	}
+}
+
 func TestInvalidateSubscriptionCacheWithZeroUserDeletesTopicPrefix(t *testing.T) {
 	oldRuntime := groupMsgRuntime
 	runtime := newTestGroupMessageRuntime()