diff --git a/pagure/lib/__init__.py b/pagure/lib/__init__.py
index 46c7640..52599bd 100644
--- a/pagure/lib/__init__.py
+++ b/pagure/lib/__init__.py
@@ -3710,7 +3710,11 @@ def set_custom_key_fields(session, project, fields, types, data):
             # Only Lists use data, strip it otherwise
             data[idx] = None
         else:
-            data[idx] = [item.strip() for item in data[idx].split(',')]
+            if data[idx]:
+                data[idx] = [
+                    item.strip()
+                    for item in data[idx].split(',')
+                ]
 
         if key in current_keys:
             issuekey = current_keys[key]