diff --git a/openpype/hosts/nuke/plugins/load/load_sequence.py b/openpype/hosts/nuke/plugins/load/load_sequence.py
index 5f2128b10f..003b406ee7 100644
--- a/openpype/hosts/nuke/plugins/load/load_sequence.py
+++ b/openpype/hosts/nuke/plugins/load/load_sequence.py
@@ -76,6 +76,8 @@ class LoadSequence(api.Loader):
         file = file.replace("\\", "/")
 
         repr_cont = context["representation"]["context"]
+        assert repr_cont.get("frame"), "Representation is not sequence"
+
         if "#" not in file:
             frame = repr_cont.get("frame")
             if frame:
@@ -170,6 +172,7 @@ class LoadSequence(api.Loader):
         assert read_node.Class() == "Read", "Must be Read"
 
         repr_cont = representation["context"]
+        assert repr_cont.get("frame"), "Representation is not sequence"
 
         file = api.get_representation_path(representation)
 
diff --git a/openpype/hosts/standalonepublisher/plugins/publish/extract_thumbnail.py b/openpype/hosts/standalonepublisher/plugins/publish/extract_thumbnail.py
index 24690cb840..23f0b104c8 100644
--- a/openpype/hosts/standalonepublisher/plugins/publish/extract_thumbnail.py
+++ b/openpype/hosts/standalonepublisher/plugins/publish/extract_thumbnail.py
@@ -116,7 +116,7 @@ class ExtractThumbnailSP(pyblish.api.InstancePlugin):
 
         # create new thumbnail representation
         representation = {
-            'name': 'jpg',
+            'name': 'thumbnail',
             'ext': 'jpg',
             'files': filename,
             "stagingDir": staging_dir,