Attributes & Anonymous Blocks

[coltcolt3825]

Hello,

Recently I have been updating my block library to make them have dynamic properties, specifically attributes. I’m the past I taught myself how to create our title block to contain attributes and experienced no issues. When I decided to go back and modify my existing blocks to contain attributes, I began noticing the *U blocks within the attribute manager field. I found out these are anonymous blocks and automatically created by Autocad to assist with dynamic blocks. 

my question is, why do these anonymous blocks appear for some of my blocks with attributes and not others? There appears to be no correlation on whether the block is dynamic or not as I have some dynamic blocks that do not have the anonymous block appear in the attributes manager and some do. 
I have also tried sync-ing the blocks, re-creating the attributes and I can also purge the anonymous blocks but as soon as I double click the block to edit parameters, they appear again. 
these anonymous blocks don’t appear in my block list, only in the attributes manager as duplicates of my blocks. 

[Libbya]

My understanding is that the anonymous blocks appear whenever a block insertion deviates from the as-drawn block definition.  The anonymous block definition automatically appears whenever any parameter or attribute within a block is edited making the current insertion different from the block definition.  I believe it is just a way for autocad to remember each insertion's specific variation.  

[coltcolt3825]

Ah okay. That would make sense then. If I saved the block reference as “X” and then I inserted it and went to change it to “Y” it would need to still be referencing “X” as the block reference. Thank you!