diff --git a/pkg/symbolizer/debuginfod_client.go b/pkg/symbolizer/debuginfod_client.go
index 6f7bde8c81..12fa3b2489 100644
--- a/pkg/symbolizer/debuginfod_client.go
+++ b/pkg/symbolizer/debuginfod_client.go
@@ -119,8 +119,10 @@ func (c *DebuginfodHTTPClient) FetchDebuginfo(ctx context.Context, buildID strin
 
 	if found, _ := c.notFoundCache.Get(sanitizedBuildID); found {
 		status = statusErrorNotFound
+		c.metrics.cacheOperations.WithLabelValues("not_found", "get", statusSuccess).Inc()
 		return nil, buildIDNotFoundError{buildID: sanitizedBuildID}
 	}
+	c.metrics.cacheOperations.WithLabelValues("not_found", "get", "miss").Inc()
 
 	v, err, _ := c.group.Do(sanitizedBuildID, func() (interface{}, error) {
 		return c.fetchDebugInfoWithRetries(ctx, sanitizedBuildID)
@@ -214,6 +216,7 @@ func (c *DebuginfodHTTPClient) fetchDebugInfoWithRetries(ctx context.Context, sa
 		// Don't retry on 404 errors
 		if statusCode, isHTTPErr := isHTTPStatusError(err); isHTTPErr && statusCode == http.StatusNotFound {
 			c.notFoundCache.SetWithTTL(sanitizedBuildID, true, 1, c.cfg.NotFoundCacheTTL)
+			c.notFoundCache.Wait()
 			c.metrics.cacheOperations.WithLabelValues("not_found", "set", statusSuccess).Inc()
 			c.metrics.cacheSizeBytes.WithLabelValues("not_found").Set(float64(c.notFoundCache.Metrics.CostAdded()))
 			return nil, buildIDNotFoundError{buildID: sanitizedBuildID}
diff --git a/pkg/symbolizer/symbolizer.go b/pkg/symbolizer/symbolizer.go
index c4dbab1621..3eaacf7c68 100644
--- a/pkg/symbolizer/symbolizer.go
+++ b/pkg/symbolizer/symbolizer.go
@@ -384,11 +384,12 @@ func (s *Symbolizer) symbolizeWithTable(table *lidia.Table, req *request) {
 
 func (s *Symbolizer) getLidiaBytes(ctx context.Context, buildID string) ([]byte, error) {
 	if client, ok := s.client.(*DebuginfodHTTPClient); ok {
-		if found, _ := client.notFoundCache.Get(buildID); found {
-			s.metrics.cacheOperations.WithLabelValues("not_found", "get", statusSuccess).Inc()
-			return nil, buildIDNotFoundError{buildID: buildID}
+		if sanitizedBuildID, err := sanitizeBuildID(buildID); err == nil {
+			if found, _ := client.notFoundCache.Get(sanitizedBuildID); found {
+				s.metrics.cacheOperations.WithLabelValues("not_found", "get", statusSuccess).Inc()
+				return nil, buildIDNotFoundError{buildID: buildID}
+			}
 		}
-		s.metrics.cacheOperations.WithLabelValues("not_found", "get", "miss").Inc()
 	}
 
 	lidiaBytes, err := s.fetchLidiaFromObjectStore(ctx, buildID)