In TDM Portal Version 126.96.36.199, where generators are using pre-action of truncating a table in database with SQL or Javelin flow are not working. This functionality was working in earlier version 188.8.131.52.
Defect in the version 184.108.40.206.
Release : 4.9.1
Component : CA Test Data Manager
If anyone facing the same issue, please open a support case and request the latest version of TDM Portal which should resolve the issue.