diff --git a/openpype/hosts/flame/plugins/publish/extract_subset_resources.py b/openpype/hosts/flame/plugins/publish/extract_subset_resources.py
index 4598405923..fd0ece2590 100644
--- a/openpype/hosts/flame/plugins/publish/extract_subset_resources.py
+++ b/openpype/hosts/flame/plugins/publish/extract_subset_resources.py
@@ -236,8 +236,8 @@ class ExtractSubsetResources(openpype.api.Extractor):
 
             # define kwargs based on preset type
             if "thumbnail" in unique_name:
-                export_kwargs["thumb_frame_number"] = in_mark + (
-                    source_duration_handles / 2)
+                export_kwargs["thumb_frame_number"] = int(in_mark + (
+                    source_duration_handles / 2))
             else:
                 export_kwargs.update({
                     "in_mark": in_mark,