why when i combine PDFs i get the content of the first page for all pages in the thumbnails

In Adobe Pro i am using the option "combine files in acrobat". I have pulled the document through the combined document screen. (Please note this error only occurs when combining word documents and not excel documents).

When the document is pulled through it shows the first page and the remaining pages stacked behind it. When i open the document, the first page shows through as every remaining page showing as identical to the first page.

I sometimes have hundreds of pages with appendices sheets and I cannot merge the document correctly as I cannot see the correct content of each individual sheet.

At present I have to merge the document, save it and then re-combine the document in order to get it into its correct format. Once I have saved the original version as a pdf it shows me the correct sheets / text. This means for every document I am having to go through the process two (or sometimes more) times in order to get the document as it should be, Please could anybody help with this error as it is causing me havoc and slowing my productivity down.

Many Thanks