Please do the below to resolve this issue:
Please navigate to your \HSoft\Doc to locate and rename the Compile folder by placing the word old at the end of the file name.
Create a new folder in this location called Compile
Open Document Manager, Select View, and then Collated Documents. Ensure this is empty. If anything reflects here please remove them.
Once empty please add a few different documents to collate, it should now execute correctly.
*Please note: At times the issue could also be due to one of the documents in the Collated lists, we can check if Protected View is not enabled and then collate.