I was following some exercises from the book “Expert Oracle Database Architecture” where the author is demonstrating the flashback feature using SQLPlus. I was copying the commands using SQLcl instead and noticed that the command flashback table emp to scn :scn;
where :scn was set to a valid scn number was giving an error. I tested the exact same commands in SQLPlus and it ran as expected so I'm thinking this might be a bug with SQLcl? I am on SQLcl version 25.2.
Here are the same commands entered in both SQLcl and SQLPlus
SQLcl:

SQLPlus:

In the SQLcl example you can see the :scn variable clearly has something bound to it even though the error indicates there is not. It seems something may be specifically wrong with the flashback command.