Solved! Go to Solution.
Just in case anyone has this same issue, I'm adding some changes I had to make for finding the doc type. We have users who attach files with periods in the file names (ex. product name version 1.0 business case.docx). Using the previous solution would pull the 0 and %20 as the doc type. To fix this I added another hidden data label and added an expression (expLast4) to pull the last four characters [Right (File Name, 4)] and I changed the hdnDocType data label expression to replace the period (in case it was a doc type with only 3 characters) [Replace (expLast4, . , (Empty String)) and this resolved the issue.