diff --git a/storage/storage_dest.go b/storage/storage_dest.go
index 5f54459e9f..b1a8341fd8 100644
--- a/storage/storage_dest.go
+++ b/storage/storage_dest.go
@@ -389,6 +389,7 @@ func (s *storageImageDestination) tryReusingBlobAsPending(blobDigest digest.Dige
 
 	// Check if we've already cached it in a file.
 	if size, ok := s.lockProtected.fileSizes[blobDigest]; ok {
+		// FIXME: What ensures layer identification?
 		return true, private.ReusedBlob{
 			Digest: blobDigest,
 			Size:   size,
@@ -451,12 +452,13 @@ func (s *storageImageDestination) tryReusingBlobAsPending(blobDigest digest.Dige
 
 	if options.TOCDigest != "" && options.LayerIndex != nil {
 		// Check if we have a chunked layer in storage with the same TOC digest.
-		layers, err := s.imageRef.transport.store.LayersByTOCDigest(options.TOCDigest)
+		layers, err := s.imageRef.transport.store.LayersByTOCDigest(options.TOCDigest) // FIXME: We can’t find this layer later!
 
 		if err != nil && !errors.Is(err, storage.ErrLayerUnknown) {
 			return false, private.ReusedBlob{}, fmt.Errorf(`looking for layers with TOC digest %q: %w`, options.TOCDigest, err)
 		}
 		if len(layers) > 0 {
+			// FIXME: createNewLayer currently requires diffID to be set if .diffOutput is not set
 			s.lockProtected.indexToTOCDigest[*options.LayerIndex] = options.TOCDigest
 			return true, private.ReusedBlob{
 				Digest:             blobDigest,
@@ -625,7 +627,7 @@ func (s *storageImageDestination) singleLayerIDComponent(layerIndex int, blobDig
 	defer s.lock.Unlock()
 
 	if d, found := s.lockProtected.indexToTOCDigest[layerIndex]; found {
-		return d.Hex() + "-toc", found
+		return d.Hex() + "-toc", found // FIXME: If this is the first layer, this is not a valid ID.
 	}
 
 	d, found := s.lockProtected.blobDiffIDs[blobDigest]