Merge pull request #5243 from tokejepsen/bugfix/maya_arnold_prefix_none

openpype/hosts/maya/api/lib_renderproducts.py

@@ -274,12 +274,14 @@ class ARenderProducts:
                 "Unsupported renderer {}".format(self.renderer)
             )
 
+        # Note: When this attribute is never set (e.g. on maya launch) then
+        # this can return None even though it is a string attribute
         prefix = self._get_attr(prefix_attr)
 
         if not prefix:
             # Fall back to scene name by default
-            log.debug("Image prefix not set, using <Scene>")
-            file_prefix = "<Scene>"
+            log.warning("Image prefix not set, using <Scene>")
+            prefix = "<Scene>"
 
         return prefix