# In 2022.3 project I had an attribute named 'Seed' after upgrading to 6000.x versions this property was duplicated and in Custom attribute section we now have 'Seed' and 'Seed_1" attributes and an error thrown to the console.
# Deleting that 'Seed' attribute from blackboard also deleted 'Scale' block from Output context

1. How to reproduce:
# Import the attached package to 6000.x version
# Open Smoke1 VFX
# Observe that there are custom attributes of 'Seed' and 'Seed_1" and error message in the console

Expected result:
# Seed is converted to Seed_1 and port connections remain the same
# Seed attribute is removed from Custom Attributes list after version upgrade
# User is informed in console message that Seed name changed to Seed_1 in user friendly language

Actual result: Seed and Seed_1 is in Custom property list and error message is thrown to the console "Exception while sanitizing model: Set 'Seed' Random (Per-component) (Vector2) of type UnityEditor.VFX.Block.SetCustomAttribute: System.ArgumentOutOfRangeException: Index was out of range. Must be non-negative and less than the size of the collection.
Parameter name: index
  at System.Collections.Generic.List`1[T].get_Item (System.Int32 index) [0x00009] in <a6d715f5ce8c4754a140b50ff638878a>:0 
  at System.Collections.ObjectModel.ReadOnlyCollection`1[T].get_Item (System.Int32 index) [0x00000] in <a6d715f5ce8c4754a140b50ff638878a>:0 "

2. How to reproduce:
# Delete Seed attribute from blackboard (This Seed attribute was connected to Scale.XZ port in 22.3 stream)

Actual result: Seed is deleted and Scale.XZ block is also deleted

Expected result: Clipboard operations for Custom attributes are not shared among other graph elements i.e it does not delete blocks

Notes:
* If issue is not reproducible after trying once, close and reopen your project and try again