I changed the type of a field from integer to TXT and after losing all the information of this field, I am not able to recover the lost information

We have a field "Adobe ID", which is the identification key of the "Profile" table and which used to be an integer, mandatory and unique field (one adobe ID per client).

Once we changed the type from integer to TXT, due to external reasons, all of the clients lost the Adobe ID information. 

To revert this,we were able to generate a historical document, with the clients and their respective Adobe IDs. The idea was to create an "update" workflow (which you can see in the image below)

When started, the workflow generated an error in the update activity (like shown in the images).

We are struggling to understand why this is happening and can not understand why the Adobe IDs are not being updated on the clients. Would anyone be able to help?