Concat function not viewable by specific people

Hi all,

Trying to figure something out.  Doing some spreadsheets for a client and I used the concat function in some of the columns, the client is unable to see anything in those columns.  It is just completely blank for them, it isn't even showing the function or anything.  Just nothing in there like I didn't fill it out.  Others inside my org are able to open it and see the results.  The vendor the spreadsheet is for can open it and see the results.

But the client cannot see the results.

He even saved a copy directly from the version I sent and sent it back to me.... and the columns are all filled out for me, but on his excel (latest version from O365 same as me) he is unable to see them.

Any ideas on why this is and or how to fix it as he wants to review before the vendor uploads the data.

Thanks in advance,

Derek