Why is the option "Process Item Grouping Change" disabled for an inventory organization?

Summary:

***Below if for informative purposes only for others who may face issues when trying to change Definition Org to a Reference Org. This is not a question or concern from / for me. ***

When try to change a Definition Inventory organization to a Reference organization, you would notice that the option "Process Item Grouping Change is disabled as shown below." There are a few situations where we cannot change a Definition org to a reference org, And below are those things that you need to check for. Sharing for informative sake.

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