truncating table involved in long running rollback

I need some help in order to understand a situation. I had an update statement on a table that for various reasons I needed to kill the session.

Smon started to take care of recovery I could see the active action by querying v$fast_start_transactions;

Because the table was a staging table part of and ODI job and because ETA for recovery was 25
hours (very suspicions this is something I need to investigate) I decided to truncate the table to release the locks and restart the job.

But after truncate the rollback still continued to run behind the scenes. Even so apparently the locks were release from the table.

Is it expected to have the recovering running after truncate?

Version: 12.1.0.2

Thank you.

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