It would be an idea to do “Clean-build” once. I mean, you should remove old binaries and recreate them by compiling all *.groovy files to *.class.
- close the Katalon Studio project
- take a full back-up of the project directory just in case
- in the project directory, remove the following folders (these will be recreated when you reopen the project)
- bin/
- Libs/
- in the project directory, remove the following files
- .cache
- .classpath
- .project
- re-open the project.