Garbled Text When Combining PDF's

Good Afternoon Everybody,

So I have been having issues with several user now. When user combined PDF's they get the below error:

What I did, I got the word and excel docs, convert them myself and they still come out like the picture above. The document above, was a new document copied from the PDF and on my end it worked fine but the accounting user saw the above document.

Version of Adobe is 18.011.20063 which is the latest one.

Anybody have an idea as to why it could happen?

Thanks,