What are the "random symbols" you are talking about?
Please provide a SMALL repeatable example of exactly what you are doing so others can attempt to replicate the behavior you are seeing.
Also povide sqlcl version.
What does "bototest5.sql" contain?
What is the OS you are using?
It appears from the mininal information you have posted, it is badly formatted or badly interpreted definitions of control characters or control character usage.