The use of variables in the From and To field inside an FTP job is not possible anymore.
Once any follow up action is done the values switch to either a connection object name or Agent file system.
Defect
Release : 4.0.7 and higher
Component : RA FTP Solution
Solution:
Update to a fix version listed below or a newer version if available.
Fix version:
Component(s): RA FTP Solution
RA.FTP 4.0.10 - scheduled release mid April 2021
Article title: How to register to Broadcom Software Product updates and Critical Alerts
https://knowledge.broadcom.com/external/article?articleId=133819