Hello, I am looking for help with document uploads in Appian.

For your use case you can try something like this. First you can change your mapping (in fileUploadField) so that each time user uploads a file, a new document will be created in your target folder (instead of single doc with multiple version). In this way you get different documentId for each time user uploads a file. You can have an additional pv variable (to have a copy of prev uploaded doc obj). Whenever user goes back and forth, you can compare the prev and current doc obj. If they are same no issue, else you can delete the prev doc obj from target folder and copy the new obj again into the additional pv. The loop continues.

If you think this approach is not effective, everytime a file is uploaded in Form_2, you can upload them in a temp folder say Folder_A. But remember your process variable will always have the latest uploaded doc. So when you finally submit the third form or at end of your process move only the recent document to Folder_B (your actual application folder) and cleanup everything in Folder_A at one shot.

These are like a workaround and may not be an effective solution. Lets wait for other people to comment.

For your use case you can try something like this. First you can change your mapping (in fileUploadField) so that each time user uploads a file, a new document will be created in your target folder (instead of single doc with multiple version). In this way you get different documentId for each time user uploads a file. You can have an additional pv variable (to have a copy of prev uploaded doc obj). Whenever user goes back and forth, you can compare the prev and current doc obj. If they are same no issue, else you can delete the prev doc obj from target folder and copy the new obj again into the additional pv. The loop continues.

If you think this approach is not effective, everytime a file is uploaded in Form_2, you can upload them in a temp folder say Folder_A. But remember your process variable will always have the latest uploaded doc. So when you finally submit the third form or at end of your process move only the recent document to Folder_B (your actual application folder) and cleanup everything in Folder_A at one shot.

These are like a workaround and may not be an effective solution. Lets wait for other people to comment.